Skeletal Muscular system

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Skeletal Muscular system
Objectives
Know muscle
Group or compartment
Location
Function
Origin and insertion
Innervation
Synergists and antagonists
Skeletal Muscular system
voluntary movements of body through space
includes skeletal striated muscle
every cell innervated (neuropathy or denervation  atrophy)
(levels of severity: neuropraxia, axonotmesis, neurotmesis)
Origin – stationary point of muscle attachment
Slip – segmented origin
Insertion – affected point of muscle attachment
Gaster – muscle belly, contractile, muscular and connective tissues
Dense regular connective tissues
Tendon – dense regular connective tissue often used as origin or
insertion
Aponeurosis – flat, sheet-like tendon
Endomysium – invests muscle fibers (cells)
Perimysium – invests muscle fascicles
Epimysium or fascia – invests entire muscle gaster
or groups of muscles into compartments
Skeletal Muscular system
Synergist – muscles with similar function, usually in the same
compartment and with the same innervation
Antagonist – muscles with opposing function, usually in opposite
compartments and with different innervation, but sometimes
antagonists work synergistically
Facilitator or fixator – a muscle that stabilizes the origin of another
Intrinsic – located within the structure that is affected
Extrinsic – located outside the structure that is affected
Naming of muscles based on any combination of the following:
Shape – e.g., teres major, deltoideus, triceps, digastric
Location – e.g., brachialis, temporalis, popliteus, tibialis anterior
Function – e.g., supinator, rotatores
Origin and/or insertion – e.g., iliacus, subscapularis, flexor carpi ulnaris
Names of muscles are minimal, therefore potentially ambiguous
Flexor digitorum superficialis – antebrachium
Flexor digitorum longus – crus
Extensor digitorum longus – crus
Extensor digitorum communis – antebrachium
General rules of function and innervation by muscle group
Cranial – cranial nerves
Cervical – cranial nerves (except vertebral axial muscles)
Visceral – nV, nVII, nIX, X
Epibranchial - nXI
Hypobranchial of “infrahyoid” – (Ansa Cervicalis: nXII and C1-C3)
Axial (postcranial, including cervical and trunk) – spinal nerves
Epaxial – dorsal rami
Hypaxial – ventral rami
Appendicular – definitive nerves via plexuses from ventral rami of spinal nerves
Ventral mass muscles (flexors, adductors, pronators) –
preaxial nerves or anterior divisions of plexus
Dorsal mass muscles (extensors, abductors, supinators) –
postaxial nerves or posterior divisions of plexus
Muscle groups and generalizations
Axial muscles – muscles that affect the axial skeleton
most both originate and insert on the axial skeleton
Head and Neck
Extrinsic ocular – muscles of ocular gaze, innervation by nIII, nIV, nVI
Intrinsic ocular – smooth muscle within eye, innervation by nIII
Muscles of mastication – insertion on mandible, innervation by nV (and ½
by nVII)
Muscles of facial expression – innervation by nVII
Intrinsic muscles of the tongue – within tongue, innervation by nXII
Extrinsic muscles of the tongue – move tongue relative to oral cavity,
innervation by nXII
Muscles of the styloid process (not a real group)
Muscles of floor of oral cavity (not a real group)
Muscles of soft palate – very small, assist in swallowing
Pharyngeal constrictors – assist in swallowing, innervation by nX
Muscles of the Larynx – innervation by recurrent laryngeal branch of nX
Epibranchial muscles – trapezius and sternocleidomastoid, innervation by
nXI
Hypobranchial (“Infrahyoid”) muscles – mostly small muscles of anterior
cervical region
innervation by Ansa Cervicalis (nXII, C1-C3)
Muscle groups and generalizations
Axial – Neck and torso, all muscles segmental
Epaxial – dorsal axial musculature, innervation by dorsal rami of spinal
nerves
Superficial layer – few and far between
Middle layer – long muscle fibers that diverge bilaterally superiorly
Deep layer – short muscle fibers that diverge bilaterally inferiorly
Hypaxial – ventral axial musculature, innervation by ventral rami of spinal
nerves
Cervical – scalene and longus muscles
Thoracic – three layers of intercostal muscles
Abdominal – three layers of abdominal oblique muscles plus rectus
abdominis
Diaphragms
Respiratory diaphragm
Pelvic diaphragm
Urogenital diaphragm
Appendicular muscles
any muscle that affects a limb or its girdle – therefore (almost) any muscle that
inserts on a limb or its girdle, even if the origin is from the axial skeleton
always innervated by definitive nerves that arise from plexuses
several spinal nerves → plexus → several definitive nerves
Pectoral limb and girdle – brachial plexus
Pelvic limb and girdle – lumbosacral plexus (=lumbar and sacral plexuses)
appendicular muscles originating from axial skeleton are often segmented (slip)
superficial muscles usually travel across more joints than deeper muscles
Pectoral Limb and Girdle
Origin from torso
Anterior – pectoral flexors and adductors
(innervation cannot be generalized)
superficial – insert on scapula and humerus
deep – insert on scapula and clavicle
Posterior – pectoral extensors and abductors
(innervation cannot be generalized)
superficial insert on scapula and humerus
deep – scapular elevators
Rotator cuff – humeral rotators
anterior – 1 medial rotator, i.e., subscapularis muscle
innervated by subscapular nerve
posterior – 3 lateral rotators
(innervation cannot be generalized)
Pectoral Limb and Girdle
Brachium
Anterior – brachial and antebrachial flexors, adductor
all innervated by musculocutaneous nerve
Superficial – muscle traverses two joints
Deep – muscles traverse one joint
Posterior – brachial and antebrachial extensors, abductor, rotator
(innervation cannot be generalized)
Pectoral Limb and Girdle (cont’d)
Antebrachium
Anterior – flexors and pronators
innervation by median nerve (and 1½ by ulnar nerve)
Superficial – origin from medial epicondyle of humerus
Deep – origin within antebrachium
Posterior – extensors and supinators
all innervated by radial nerve
Superficial
origin from supracondylar crest of humerus
origin from lateral epicondyle of humerus
Deep – origin from within antebrachium
insertion on pollex (except 1)
Manus
Thenar – muscles of the pollex
innervation by median nerve
Hypothenar – muscles of digiti minimi
innervation by ulnar nerve
Interossei – originate from metacarpals
innervation by ulnar nerve
Pectoral limb and girdle
Major branches of brachial plexus (from spinal nerves C5 – C8, T1)
Dorsal scapular nerve – rhomboid muscles
Suprascapular nerve – rotator cuff
Subscapular nerve – subscapularis and teres major (medial brachial rotators)
Long thoracic nerve – serratus anterior
Thoracodorsal nerve – latissimus dorsi
Medial and lateral Pectoral nerves – pectoralis major and minor
Axillary nerve – deltoideus and teres minor
Radial nerve – triceps and posterior antebrachium
Musculocutaneous nerve – anterior brachium
Median nerve – anterior antebrachium and thenar
Ulnar nerve – 1½ medial antebrachial muscles, hypothenar, interossei
Pelvic Limb and Girdle
Origin from torso
Anterior – iliopsoas group, abdominal flexors of the femur
insert on lesser trochanter
innervation by femoral nerve
Posterior
superficial – gluteal group, femoral extensors and abductors
origin from false pelvis
innervation by gluteal nerves
deep – femoral rotators
origin from true pelvis and sacrum
Pelvic Limb and Girdle
Femur
Anterior – quadriceps and sartorius, crural extensors
all innervated by femoral nerve
Posterior – ‘hamstrings’ muscles, femoral extensors and crural flexors
origin from ischial tuberosity (except ½)
innervation by tibial nerve (except ½)
Medial – femoral adductors
origin from true pelvis
most insert on linea aspera
all innervated by obturator nerve
Pelvic Limb and Girdle (cont’d)
Popliteal
origin from lateral condylar region of femur
Crus
Anterior – pedal dorsiflexors and invertor, digital extensors
all innervated by peroneal nerve
Lateral – pedal evertors
all innervated by peroneal nerve
Posterior
all innervated by tibial nerve
Superficial (sural) – pedal plantarflexors
Deep – pedal plantarflexor and invertor, digital flexors
1:1 antagonists of anterior crural muscles
Pes
Dorsum
digital and pedal extensors
all innervated by terminal branch of peroneal nerve
Plantar
digital flexors, adductors, and abductors
all innervated by terminal branches of tibial nerve
Pelvic limb and girdle
Major branches of lumbar plexus (from spinal nerves L2 – L4 )
Obturator nerve – medial femoral
Femoral nerve – iliopsoas and anterior femoral
Major branches of sacral plexus (from spinal nerves L4 – L5, S1 – S3)
Superior and inferior Gluteal nerves – gluteal group
Sciatic nerve
Tibial nerve – posterior femoral and posterior crural, plantar pes
Peroneal or Common peroneal nerve – anterior and lateral crural,
dorsum pedis
And now onto the detailed muscle descriptions…
Muscles of the Orbit
6 Extrinsic ocular muscles
muscles of ocular gaze
4 rectus muscles – “straight” muscles
Superior – elevation
Medial – adduction and convergence
Lateral – abduction and divergence
Inferior – depression
2 oblique muscles
Superior – rotation (intorsion), depression, abduction
Inferior – rotation (extorsion), elevation, abduction
Levator palpebrae superioris
all innervated by nIII oculomotor except:
Superior ocular oblique – nIV trochlear nerve
Lateral ocular rectus – nVI abducens nerve
Ptosis – drooping eyelid, deficit of nIII (midbrain nucleus)
Ophthalamoparesis – inability to direct ocular gaze
Inability to abduct eye, deficit of nVI (hindbrain nucleus)
Muscles of mastication
Mandibular adductors/elevators
all innervated by nV3 mandibular branch of trigeminal
Temporalis
mandibular adductor and retractor
Origin from temporal fossa and line
Inserts on coronoid process
Masseter
mandibular adductor and protractor
Origin from zygomatic arch
Inserts on lateral mandibular ramus and angle
Medial Pterygoideus
lateral mandibular movement
Origin from medial pterygoid plate of sphenoid
Inserts on medial mandibular ramus
Lateral Pterygoideus
mandibular protraction
Origin from lateral pterygoid plate of sphenoid
Inserts on superior medial mandibular ramus
Muscles of mastication
Mandibular abductor/depressor
Digastric
Posterior belly
Origin from mastoid process
Innervation by nVII facial nerve
Central tendon
passes thru trochlea of lesser cornu of hyoid
Anterior belly
Inserts on posterior mandibular symphysis
Innervation by nV3 mandibular branch of trigeminal nerve
Muscles of facial expression
All innervated by by nVII facial nerve
Platysma – covers anterior cervical region
Occipitofrontalis or epicranius – supports scalp
Frontalis
Galea aponeurotica
Occipitalis
Buccinator – lines lateral oral cavity
Orbicularis oculi – ring around orbit
Orbicularis oris – ring around mouth
Zygomaticus major and minor
Levator anguli oris
Depressor anguli oris
Risorius – the smiling muscle
Bell’s palsy – facial muscle paralysis, drooping face, deficit of nVII
Intrinsic muscles of the tongue
within tongue, affect the shape of tongue
Innervation by nXII hypoglossal nerve
Longitudinal fascicles
Transverse fascicles
Vertical fascicles
(major) Extrinsic muscles of the tongue
move tongue relative to oral cavity
Innervation by nXII Hypoglossal nerve
Genioglossus
lingual protractor
Origin from mandibular symphysis
Styloglossus
lingual retractor and elevator
Origin from styloid process of temporal
Hyoglossus
lingual retractor and depressor
Origin from body and greater cornu of hyoid
Muscles originating from styloid process of temporal bone
Listed from anterior to posterior:
Styloglossus (extrinsic muscle of the tongue)
Stylohyoideus
elevates hyoid during swallowing
Insertion on greater cornu of hyoid, nearest lesser cornu
bifurcates around central tendon of digastric
Stylopharyngeus
elevates larynx during swallowing
Insertion on thyroid cartilage of larynx
Muscles of soft palate
small muscles that assist in swallowing
Tensor veli palatini – opens pharyngotympanic tube (Eustachian
canal)
Levator veli palatini
Salpyngopharyngeus
Uvulus
Pharyngeal constrictors
muscles that circle the pharynx and assist in swallowing
Innervation by vagus nerve
Superior constrictor
Middle constrictor
Inferior constrictor
Intrinsic Laryngeal Muscles
small muscles that control vocal chords and speech
Innervation by recurrent laryngeal branch of nX vagus nerve
Arytenoideus
Muscles of floor of oral cavity
listed from superior to inferior or deep to superficial
Genioglossus (extrinsic muscle of the tongue)
Geniohyoid
Origin from posterior mandibular symphysis
Insertion on body of hyoid
Innervation by Ansa Cervicalis
Mylohoid
Origin from mylohyoid line of medial mandibular body
Insertion on body of hyoid
Innervation by branch of nV3 Mandibular Nerve
Anterior belly of digastric (muscle of mastication, nV3)
Platysma (muscle of facial expression, nVII)
Hypobranchial or “Infrahyoid” muscles
small segmental muscles of anterior cervical region extending from
pectoral girdle to mandible
Innervation by Ansa Cervicalis
roots from nXII Hypoglossal nerve and spinal nerves C1-C3
Sternothyroideus
Origin from manubrium deep and medial to sternohyoid
Inserts on thyroid cartilage of larynx
Sternohyoideus
Origin from manubrium superficial and lateral to sternothyroid
Insertion on hyoid lateral to thyrohyoid, medial to omohyoid
Thyrohyoideus
Origin from thyroid cartilage of larynx
Insertion on body of hyoid
Omohyoideus
Origin from superior margin of scapula
Restrained by fascia of clavicle
Insertion on greater cornu of hyoid lateral to sternohyoid
Epibranchial muscles
Innervation by nXI spinal accessory nerve
Trapezius
cranial and cervical extensor
scapular elevator, depressor, and rotator (inferior angle laterally)
Origins: superior nuchal line, nuchal ligament, spines of all
thoracic vertebrae
Insertion on scapular spine, acromion, and lateral 1/3 of clavicle
superficial to latissimus dorsi where they overlap (T7-T12)
deficit - inability to abduct brachium above horizontal (same as deficit of
serratus anterior muscle or long thoracic nerve)
Sternocleidomastoid
cranial and cervical flexor and rotator
Inserts on mastoid process of temporal bone
Sternomastoid
Origin from manubrium
Cleidomastoid
Origin from sternal extremity of clavicle
Triangles of the neck
Posterior triangle
Superior belly of the trapezius, sternocleidomastoid, and clavicle
Anterior triangle
Sternocleidomastoid, inferior margin of the mandible, and
midsagittal plane
Submandibular or submaxillary triangle
Inferior margin of mandible and anterior and posterior bellies of
the digastric
Carotid triangle
Posterior belly of the digastric, superior belly of the omohyoid,
and sternocleidomastoid
Superficial layer of Epaxial Muscles
Innervation by dorsal rami of spinal nerves
Splenius (capitis and cervicis) – the “bandage”
cranial and cervical extensor
(unilaterally an abductor or “lateral flexor” - ugh)
deep to superior part of trapezius
Origin from nuchal ligament and spines of cervical and uppermost
thoracic vertebrae
Inserts on transverse processes of cervical vertebrae, lateral superior
nuchal line and mastoid processes
Serratus posterior superior
costal elevator
Origin from lower cervical and upper thoracic vertebrae
Inserts on costae 2 thru 5
Serratus posterior inferior
Costal depressor
Origin from lower thoracic and upper lumbar vertebrae
Inserts on costae 9 thru 12
Middle layer of Epaxial Muscles
long muscle fibers that diverge laterally superiorly
Innervation by dorsal rami of spinal nerves
Erector spinae
Listed from lateral to medial:
Iliocostalis
Origin from sacrum and iliac crest
Inserts on costae and transverse processes of cervical vertebrae
Longissimus
Origin form sacrum and transverse processes
Inserts on transverse processes and costae
Spinalis
Both originates and inserts on spinous processes
Deep layer of Epaxial Muscles
short muscle fibers that diverge laterally inferiorly
Innervation by dorsal rami of spinal nerves
Transversospinalis
Origin from transverse process
Inserts on spinous process of superior vertebrae
Listed from lateral to medial, superficial to deep:
Semispinalis
Fascicles travel 6 vertebrae
Multifidis
Fascicles travel 4 vertebrae
Long rotatores
Fascicles travel 2 vertebrae
Short rotatores
Fascicles travel 1 vertebra
Deep layer of Epaxial Muscles (cont’d)
Levators costarum
Origin from transverse processes
Inserts on angle of inferior costae
Long
Short
Quadratus lumborum
Forms posterior wall of abdominal cavity
Origin from iliac crest
Inserts on lumbar transverse processes and 12th costa
Hypaxial muscles
Innervation by ventral rami of spinal nerves
Hypaxial muscles of Cervical Region
Scalene muscles
Cervical flexors and rotators
Insertion on transverse processes of cervical vertebrae
Anterior scalenus
Origin from costa 1
Middle scalenus
Origin from costa 1
Posterior scalenus
Origin from costa 2
Relationships to other important structures
Anterior to scalenus anterior:
Phrenic nerve
Internal jugular vein and subclavian vein
Between anterior and middle scalene muscles
Subclavian artery
Roots of brachial plexus
Hypaxial muscles of Cervical Region (cont’d)
Longus muscles
Origin from cervical vertebrae
Longus colli
Cervical flexors and rotators
Insertion cervical vertebrae
Longus capitis
Cranial flexor
Inserts on occipital bone
Hypaxial muscles of Thorax
External intercostal
Fibers oriented inferomedially
Internal intercostal
Innermost intercostal
Rectus thoracis (occasional)
Transversus thoracis
Hypaxial muscles of abdomen
3 abdominal oblique muscles
equivalent to intercostal muscles
Origins from lower costae, lumbar vertebrae, iliac crest, and
inguinal ligament
Insert on linea alba via aponeuroses
External abdominal oblique
Aponeurosis forms superficial layer of rectus sheath
Internal abdominal oblique
Aponeurosis splits to form superficial and deep layers
of rectus sheath
Transversus abdominis
Aponeurosis forms deep layer of rectus sheath
Rectus abdominis – “straight muscle”
Contained within rectus sheath
Segmented by tendinous intersections
Origin from superior pubis
Inserts on costal cartilages 5 thru 7
Respiratory diaphragm
Inhalation
separates thoracic and abdominal cavities
Innervation by left and right phrenic nerves from spinal nerve C4
(and occasionally C3 or C5)
Origin from costal margin
Insertion on central tendon
Foramina for passage of structures
Esophageal hiatus – for esophagus
Aortic hiatus – for descending aorta
Caval hiatus – for inferior vena cava
paired Arcuate ligaments – for psoas minor
muscles
Pelvic diaphragm
forms floor of pelvic cavity
Levator ani
Puborectalis – the rectal sling
maintains continence
Pubococcygeus – medial
Iliococcygeus – lateral
Urogenital diaphragm
Superficial or inferior to pelvic diaphragm
Anterior to ischial tuberosities only
perforated by vagina and urethra
Pectoral Limb and Girdle - Origin from torso
Anterior superficial
Pectoralis major
Brachial flexor
Antagonist is latissimus dorsi
Origin proximal 2/3’s clavicle, sternum, and costae
Inserts on proximal anterior humerus distal to greater tubercle
Innervation by medial and lateral pectoral nerves
Serratus anterior
Holds scapula onto thorax, scapular rotator and protractor
Synergist to trapezius in scapular rotation
Origin from most costae
Inserts on vertebral border of scapula, especially inferior angle
Innervation by long thoracic nerve, deficit characterized by
“winged scapula” and inability to abduct brachium above
horizontal
Pectoral Limb and Girdle - Origin from torso
Anterior deep
Pectoralis minor
Scapular protractor
Antagonist to scapular elevators
Origin from costae 3 thru 5
Inserts on coracoid process of scapula
Innervation by lateral pectoral nerve
Subclavius
Clavicular depressor
Origin from costa 1
Inserts on inferior medial clavicle
Pectoral Limb and Girdle - Origin from torso
Posterior superficial, proximal
Trapezius (really an epibranchial muscle)
Latissimus Dorsi
Humeral extensor
Antagonist of pectoralis major
Origin (simplified) from thoracolumbar fascia of iliac crest, median
sacral crest, and spines of all lumbar and thoracic vertebrae 7 thru
12 (also a few costae and inferior angle of scapula)
Deep to trapezius where they overlap
Inserts on proximal anterior humerus immediately medial to pectoralis
major
Innervation by thoracodorsal nerve
Pectoral Limb and Girdle - Origin from torso
Posterior deep scapular elevators and adductors
all insert on vertebral border (medial margin) of scapula
listed from superior to inferior:
Levator Scapulae
Origin from nuchal ligament
Innervation by nerve to levator scapulae
Rhomboid muscles
Origin from spinous processes of C7-T4
Innervation by dorsal scapular nerve
Rhomboideus Minor – superior
Rhomboideus Major – inferior
Pectoral Limb and Girdle - Origin from torso
Posterior superficial, distal
Deltoideus
humeral abductor
Origins: scapular spine and acromion and lateral 1/3 of clavicle
(just like insertion of trapezius and just unlike origin of
pectoralis major)
separated from pectoralis major by deltopectoral triangle –
which is penetrated by cephalic vein
Insertion: deltoid tuberosity (lateral mid-diaphysis of humerus)
Teres Major
humeral medial rotator and extensor/adductor
Origin: lateral margin of scapula inferior to teres minor
Insertion: anterior proximal humerus unlike teres minor
Innervation: subscapular nerve (like subscapularis)
separated from teres minor by long head of triceps (see
quadrangular space, after triceps)
Pectoral Limb and Girdle - Origin from torso
Rotator cuff muscles
humeral rotators
responsible for integrity of glenohumeral joint
all originate form scapula
all insert on humeral tubercles
Humeral lateral rotators
all insert on greater tubercle
Listed from superior to inferior:
Supraspinatus
Origin supraspinous fossa
Innervation by suprascapular nerve
Infraspinatus
Origin from infraspinous fossa
Innervation by suprascapular nerve
Teres Minor
Origin from inferolateral margin of scapula
Innervation by axillary nerve (like deltoideus muscle)
Separated from teres major by long head of triceps (see
quadrangular space, after triceps)
Pectoral Limb and Girdle - Origin from torso
Rotator Cuff muscles - continued
humeral medial rotator
Subscapularis
Origin: subscapular fossa
Insertion: lesser tubercle
Innervation: subscapular nerve
Pectoral Limb
Brachium
Anterior compartment – brachial and antebrachial flexors
Innervation by musculocutaneous nerve
Anterior Brachium, Superficial
one muscle that completely traverses brachium without origin or
insertion on it
Biceps Brachii (not “biceps”)
brachial and antebrachial flexor
antagonist of triceps
2 Origins
Long head from supraglenoid tubercle, restrained in
intertubercular sulcus of humerus by transverse ligament
with synovial sheath
Short head from coracoid process
2 Insertions
Tendon of Biceps Brachii inserts on Radial Tuberosity
Bicipital Aponeurosis inserts on fascia of anterior
compartment of antebrachium
Anterior Brachium, Deep
Two muscles that traverse only one joint each
Innervation by musculocutaneous nerve
Coracobrachialis
proximal
humeral flexor and adductor
Origin: coracoid process
Insertion: medial mid-diaphysis of humerus
Brachialis
distal
antebrachial flexor
Origin: distal diaphysis of humerus
Insertion: coronoid process of ulna
Posterior Brachium (cont’d)
Triceps (brachii)
antebrachial (and brachial) extensor
Insertion: olecranon process of ulna
Innervation: radial nerve (like all posterior compartment antebrachial
muscles)
3 Origins:
Long head
Origin: infraglenoid tubercle of scapula
passes between teres minor and teres major muscles
along with axillary nerve and circumflex humeral artery
Medial head
Origin: distal posterior diaphysis of humerus
deep to lateral head
Lateral head
Origin: proximal extremity of posterior humerus
superficial to medial head
Quadrangular Space
Boundaries
Medial – long head of triceps
Superior – teres minor
Lateral – surgical neck of humerus
Inferior – teres major
Contents
axillary nerve
circumflex humeral artery
Anterior Antebrachium, Superficial
all but one muscle innervated by median nerve
all originate from medial epicondyle of humerus, most by common
tendon
central muscles insert more distally than more medial or lateral muscles
listed from lateral to medial:
Pronator teres
Insertion: proximal radius (anterior oblique line)
Flexor carpi radialis
carpal flexor and abductor
Insertion: pollical metacarpal
Palmarus longus - Superficial to flexor digitorum superficialis
palmar flexor
tendon anterior to flexor retinaculum, not within carpal tunnel
Insertion: palmar aponeurosis
Flexor digitorum superficialis - deep to palmaris longus
digital flexor
tendons bifurcate and insert on middle phalanges of digits II thru V
Flexor carpi ulnaris
carpal flexor and adductor
Insertion: pisiform
Innervation: ulnar nerve
Anterior Antebrachium, Deep
all originate within antebrachium
all but ½ innervated by median nerve
Flexor pollicis longus – lateral
Insertion: distal pollical phalanx
Flexor digitorum profundus – medial
four gasters corresponding to digits II thru V
tendons pass through bifurcation of tendons of flexor digitorum
superficialis
Insertions: distal phalanges of digits II-V
Innervation:
digits II and III by median nerve
digits IV and V by ulnar nerve
Pronator quadratus – deep to both of the above
oriented transversely
Origin: distal ulna
Insertion: distal radius
Posterior Antebrachium, Superficial
all innervated by radial nerve
listed from lateral to medial:
2 muscles originating from supracondylar crest of humerus
Brachioradialis or supinator longus
supinator, flexor when antebrachium is already flexed
Insertion: distal radius
Extensor carpi radialis longus
carpal extensor and abductor
4 muscles originating from lateral epicondyle of humerus
Supinator or supinator brevis (origin also from proximal ulna)
Insertion: proximal radius next to pronator teres
Extensor carpi radialis brevis
carpal extensor and abductor
Extensor digitorum communis
Insertion: extensor expansion at metacarpophalangeal (MCP)
joint
Extensor carpi ulnaris
carpal extensor and adductor
Anconeus
antebrachial extensor
Posterior Antebrachium, Deep
origins from within antebrachium
oriented obliquely
most insert on pollex
innervation by radial nerve
listed from medial to lateral (think posterior to lateral):
Supinator (also listed as superficial because of humeral head)
Extensor indicis
Extensor pollicis longus
Extensor pollicis brevis
Abductor pollicis longus
Palmar Manus
(there are no intrinsic muscles of the dorsum of the manus)
Thenar muscles
intrinsic muscles of the pollex
Innervation: median nerve
Superficial
listed from lateral to medial (think lateral to anterior):
Abductor pollicis brevis
Flexor pollicis brevis
~Adductor pollicis (not a thenar muscle!)
Innervation by ulnar nerve!
Deep
Opponens pollicis
Hypothenar muscles
similar to thenar muscles but inserting on digit V
Innervation: ulnar nerve
Layers of the Palmar manus
listed from superficial to deep:
Palmar aponeurosis
Tendons of flexor digitorum superficialis
Insert on middle phalanges
Tendons of flexor digitorum profundus
Insert on distal phalanges
Interosseous muscles
Innervation: ulnar nerve
Insert on proximal phalanges
Palmar interossei
flexors and adductors
Dorsal interossei (palmar muscle compartment)
extensors and abductors
Intrinsic muscles of digits II-V
Lumbricals
Originate bilaterally from tendons of flexor digitorum profundus
Insert on extensor expansion
Peripheral nerve deficits, causes and symptoms
Ape hand or papal hand
entrapment of median nerve at carpal tunnel or by pronator teres
atrophy of thenar muscles
lateral rotation of pollex
Claw hand
entrapment of ulnar nerve at cubital tunnel or Guyon’s canal
atrophy of adductor pollicis, hypothenar muscles, and lumbricals
abduction of digit V
flexion of digits IV and V
Drop hand
radial nerve deficit due to humerus fracture at spiral groove or lead
poisoning
flaccid flexion of carpus
Anterior muscles of pelvic girdle/limb originating from torso
lIiopsoas
abdominal flexors of the femur
common insertion on lesser trochanter
Innervation: femoral nerve
Iliacus
Origin: iliac fossa
Psoas major
Origin: lumbar vertebrae (transverse processes)
Psoas minor (variable)
Origin: lowermost costae (11 and 12)
passes thru arcuate ligaments or lateral retinacula of respiratory
diaphragm
Additional insertion on pectineal crest
Posterior muscles of pelvic girdle/limb originating from torso
Gluteal group
pelvic extensors and abductors of the femur
all except gluteus maximus innervated by superior gluteal nerve
Gluteus maximus
femoral extensor
Origin: sacrum and posteromedial iliac crest
2 Insertions: gluteal tuberosity and iliotibial tract*
Innervation: inferior gluteal nerve
Gluteus medius
femoral abductor (stabilizes pelvis when walking)
Origin: lateral iliac crest deep to gluteus maximus posteriorly
Insertion: greater trochanter
Gluteus minimus
femoral abductor (stabilizes pelvis)
Origin: lateral iliac ala deep to gluteus medius
Insertion: greater trochanter
Tensor fascia lata
locks knee in extended position (some rotation and abduction)
Origin: anterior iliac crest
Insertion: iliotibial tract
*Iliotibial tract inserts on anterior lateral tibial condyle
Deep lateral femoral rotators
Deep gluteal - listed from superior to inferior, as seen posteriorly:
Piriformis
Superior Gemellus
Tendon of Obturator Internus
Inferior Gemellus
Quadratus Femoris
not visible posteriorly (and not gluteal):
Obturator Externus
Deep lateral femoral rotators, by group
Muscle of greater sciatic foramen
Piriformis
Origin: sacrum (and iliac part of greater sciatic notch)
Insertion: greater trochanter
exits greater sciatic foramen superior (usually) to sciatic nerve
Obturator muscles
Obturator internus
Origin: posterior or internal side of bony margins of obturator
foramen and obturator membrane
Insertion: greater trochanter
Obturator externus
Origin: anterior or external side of bony margins of obturator
foramen and obturator membrane
Insertion: trochanteric fossa
deep to medial femoral compartment
tendon passes inferior to femoral neck
Deep lateral femoral rotators, by group (continued)
Muscles of lesser sciatic foramen
Superior gemellus
Inferior gemellus
Origins: lesser sciatic notch of ischium
Insertions: tendon of obturator internus
Tendon of obturator internus
Muscles of ischial tuberosity
Quadratus femoris
Origin: ischial tuberosity
Insertion: intertrochanteric crest
Anterior compartment femoral muscles
innervation by femoral nerve
Sartorius
lateral femoral rotator, femoral and crural flexor
Origin: anterior superior iliac spine
Insertion: medial condyle of tibia
Quadriceps
crural extensor (and femoral flexor)
Insertion: patella (patellar ligament inserts on tibial tuberosity)
Rectus femoris
Origin: anterior inferior iliac spine
3 Vastus muscles
Origin: nearly the entire diaphysis of femur
Vastus medialis
Vastus intermedius
posterior or deep to rectus femoris
Vastus lateralis
Posterior compartment femoral muscles (“hamstrings”)
femoral extensors and crural flexors
all but ½ originate from ischial tuberosity
all but ½ innervated by tibial nerve
Semimembranosus
medial
anterior to semitendinosus
Insertion: medial condyle of tibia
Semitendinosus
medial
posterior to semimembranosus
Insertion: medial condyle of tibia
Biceps femoris
lateral
Insertion: fibular head
Long head
Short head
Origin: linea aspera
Innervation: peroneal nerve
Medial compartment femoral muscles
femoral adductors
all originate from anterior of true pelvis
most insert on linea aspera
all innervated by obturator nerve
Medial compartment, superficial or anterior
all originate from medial pubis except pectineus
listed from medial to lateral:
Gracilis
Adductor longus
Pectineus
superficial or anterior to adductor brevis
Origin: pectineal crest
Adductor brevis
deep or posterior to pectineus
Medial compartment femoral muscles, posterior or deep
Adductor magnus
Origin: inferior rami of pubis and ischium (below obturator
foramen)
Insertion: linea aspera and adductor tubercle
Adductor hiatus – distal foramen for passage of femoral artery
Femoral triangle
Boundaries:
Inguinal ligament
Sartorius
Adductor longus
location of femoral nerve, artery, and vein, and end of great or
long saphenous vein
Popliteal Fossa
boundaries:
Semimembranosus, Semitendinosus
Biceps femoris
Medial and lateral heads of Gastrocnemius
location of popliteal artery, and end of short saphenous vein
Popliteal Muscles
Origin: posterior surface of lateral condyle of femur
Innervation: tibial nerve
Plantaris
variably present, considered vestigial
superficial to popliteus
Tendon:
passes between gastrocnemius and soleus
emerges medial to Achille’s or calcaneal tendon
passes posterior to medial malleolus
Insertion: medial calcaneal tuberosity
Popliteus
medial tibial rotator, lateral femoral rotator, ‘unlocks’ knee
deep to plantaris
Insertion: proximal posterior tibia (many consider origin and
insertion to be reverse of this since it is the femur that is
rotated)
Crus, posterior compartment, superficial (Sural muscles)
Triceps surae
plantarflexor
Insertion: calcaneual tuberosity via calcaneal or Achille’s tendon
Innervation: tibial nerve
Gastrocnemius
superficial
Medial head
Origin: medial epicondyle of femur
Lateral head
Origin: lateral epicondyle of femur
Soleus
deep
Origin: head of fibula (and posterior crest of tibia)
Crus, posterior compartment, deep
all originate within crus
1:1 antagonists of anterior crural muscles
…but orientation of origins reversed
all tendons pass posterior to medial malleolus where they cross sides
and are restrained by the flexor retinaculum
all innervated by tibial nerve
listed from lateral to medial:
Flexor hallucis longus
tendon passes thru groove in calcaneus (posterior and inferior to
sustentaculum tali)
Tibialis posterior
most anterior or deepest
plantarflexor and invertor (synergistically with tibialis anterior)
Insertion: medial pes (navicular, cuneiforms, and metatarsal I-III)
Flexor digitorum longus
Crus, anterior compartment
all originate within crus
1:1 antagonists of deep muscles of posterior crus
all tendons restrained by extensor retinaculi anterior to both malleoli
all innervated by peroneal nerve
listed from medial to lateral:
Extensor hallucis longus
Tibialis anterior
anterior to all others
pedal dorsiflexor and invertor (synergistically with tibialis posterior)
Insertion: medial pes (cuneiform I and metatarsal I)
Extensor digitorum longus
Peroneus tertius
dorsiflexor
Insertion: metatarsal V
Crus, lateral or peroneal compartment
two evertors/plantar flexors (not peroneus tertius)
both originate from fibula
tendons pass posterior to lateral malleolus
both innervated by common peroneal nerve
Peroneus longus
Origin: fibular head and proximal fibula
tendon passes thru groove between cuboid and tuberosity of
metatarsal V
Insertion: medial pes (cuneiform II and metatarsal I, near tibialis
anterior)
Peroneus brevis
Origin: mid to distal fibula
Insertion: tuberosity of metatarsal V
Dorsum Pedis
extensor hallucis brevis
extensor digitorum brevis (no equivalent muscle in manus)
Plantar Pes
somewhat arbitrarily defined layers, listed from superficial to deep:
1st layer
plantar aponeurosis
2nd layer
abductor hallucis
flexor digitorum brevis (no equivalent muscle in manus)
inserts on digits II thru V
abductor digiti minimi
3rd layer
tendons of flexor digitorum longus
quadratus plantae or flexor accessorius
4th layer
flexor hallucis brevis
adductor hallucis (three heads: transverse, oblique, medial)
flexor digiti minimi
5th layer
interosseous muscles
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