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
