Cat Muscles
Linea alba: white line of CT that separates the L/R portion of the abdominal muscles
Caudal Trunk Muscles
External oblique: most superficial; fibers orient craniodorsally.
Internal oblique: lie directly beneath the external obliques; fibers orient caudodorsally.
Transversus abdominis: lies beneath the internal obliques; fibers orient transversally.
Rectus abdominis: longitudinal band of muscles on either side of the linea alba and is encased in a sheath
formed by the aponeuroses of the other 3 abdominal muscles.
Pectoral Muscles
Pectoralis complex
Pectoralis superficialis
Pectoralis descendens/ Pectoantebrachialis: most superficial chest muscle; thin band extending
from the midline of the body to the upper portion of the forelimb.
Pectoralis transversus/ Pectoralis major: diagonally oriented band partially covered by the
clavotrapezius and clavobrachialis.
Pectoralis profundus/ Pectoralis minor: caudal and beneath the pectoralis major, thick band of muscle.
Xiphihumeralis: long, thin, narrow band of muscle that lies along the posterior border of the pectoralis
minor.
Trapezius group
Brachiocephalicus
Cleidocervicalis/ Clavotrapezius: wide flat muscle that covers most of the lateral portion of the
neck.
Cleidobrachialis/ Clavobrachialis/ Clavodeltoid: appears to be the cranial portion of the deltoid.
Cervical trapezius/ Acromiotrapezius: lies over the scapula, superficial
Thoracic trapezius/ Spinotrapezius: triangular trapezius, most posterior.
Sternocleidomastoid group
Sternomastoid: forms the apex of a V just cranial to the anterior end of the sternum while the arms
continue to the ear.
Cleidomastoid: extends between the clavicle and the temporal region of the skull; lies dorsolateral to the
sternomastoid.
Superficial shoulder muscles
Omotransversarius / Levator scapulae ventralis: lies between the clavotrapezius and acromotrapezius; medial to
the acromiodeltoid.
Deltoid
Acromiodeltoid: positioned ventral to the levator scapulae ventralis and caudal to the clavobrachialis.
Scapulodeltoid/ Spinodeltoid: lies ventral to the acromiotrapezius and caudal to the acromiodeltoid.
Latissimus dorsi: large, thick, triangular muscle that lies posterior and is covered by the spinotrapezius.
Deep Shoulder Muscles
Supraspinatus: lies in the supraspinous fossa of the scapula.
Infraspinatus: lies in the infraspinous fossa of the scapula.
Teres major: occupies the caudal border of the scapula.
Teres minor: lies between the infraspinatus and the long head of the triceps brachii, beneath the spinodeltoid.
Rhomboideus Thoracis and cervicis: thick trapezoidal muscle on the deep back.
Rhomboideus Capitis: cranial, long, flat narrow band that lies laterally and over the cervicis.
Serratus Ventralis: large, fan-shaped muscle that consists of strap-like slips that extend between thorax and the
scapula.
Subscapularis: large, medial, triangular muscle located within the subscapular fossa.
Cranial Trunk Muscles
External intercostals: outer layer of muscles lying in the intercostal spaces between adjacent ribs,
craniodorsally, similar to the external oblique layer.
Internal intercostals: lies directly medial to the external intercostals
Transversus thoracis: incomplete third layer beneath the internal intercostals.
Scalenus: 3 bands lying at an oblique angle along the lateral aspect of the thorax and cranially uniting into a
single bundle; medial to the serrates ventralis.
Rectus Thoracis/ Transversus Costarum: think, band like muscle extending from the sternum and covering the
cranial portion of the rectus abdominus muscle.
Serratus Dorsalis: thin layer that appears as slips extending along the dorsal part of the thorax and neck beneath
the latissimus dorsi.
Longus Colli: lies along the lateral aspect of the neck; narrow band of muscles medial to the scalenes.
Splenius: lies along the dorsal lateral aspect of the neck beneath the rhomboideus capitis.
Longissimus capitis: narrow, strap-like muscle that is a cranial continuation of the longissimus dorsi.
Semispinalis Cervicis and Capitis: beneath the splenius.
Multifidi/ Multifidus spinae: extensive muscle consisting of many bundles of fibers that lie above the
lumbar vertebrae.
Erector spinae/ Sacrospinalis
Iliocostalis: thin layer confined to the thoracic region; lies lateral to the longissimus over the
dorsal aspect of the ribs.
Spinalis/ Spinalis dorsi: medial subdivision of the longissimus dorsi.
Longissimus dorsi: occupies the space between the neural spines and transverse processes and extends from the
lumbar vertebrae to the cervical region.
Muscles of the Brachium and Antebrachium
Triceps brachii: long, lateral, medial head; all insert in the olecranon of the humerus.
Biceps brachii: lies on the cranial surface of the humerus; only has 1 head in the cat.
Epitrochlearis: flat, thin muscle on the medial surface of the brachium; lies partially over the triceps brachii.
Anconeus: covers the lateral surface of the elbow; small triangular muscle.
Brachialis: lateral flexor located along the cranial surface of the humerus; next to the long head of the triceps.
Coracobrachialis: lies on the medial aspect of the shoulder joint in close proximity to the ridge of the humerus.
Extensors
Brachioradialis: extends along the radial border of the antebrachium.
Extensor carpi radialis longus: lies on the radial side of the antebrachium, deep to the brachioradialis.
Extensor carpi radialis brevis: medial to the extensor radialis longus
Extensor digitorum communis: dorsal muscle that partially overlies the extensor carpi longus and brevis.
Extensor digitorum lateralis: lies lateral to the extensor digitorum communis.
Extensor carpi ulnaris: lies along the ulnar side of the antebrachium.
Abductor pollicus longus: deep, flat muscle located distal to the supinator; fibers run between the ulna
and radius.
Supinator: surrounds the proximal end of the radius and lies deep to the extensor digitorum communis
and extensor digitorum lateralis.
Flexors
Pronator teres: ventral muscle oriented obliquely over the upper surface of the forearm
Flexor carpi radialis: extends from the humerus to the metacarpals.
Flexor carpi ulnaris: lies along the ulnar side of the ventral aspect of the lower forelimb.
Flexor Digitorum Superficialis: 2-part muscle – widest of the muscles on the ventral surface.
Flexor digitorum profundus: next to the flexor digitorum ulnaris.
Pelvic and Hindlimb Muscles
Gluteus profundus/ Gluteus Minimus: deep to the gluteus medius.
Gluteus superficialis/ Gluteus Maximus: trapezoidal muscle lying just anterior to the caudofemoralis.
Gluteus Medius: medial to the tensor fascia latae and proximal to the gluteus maximus.
Piriformis: fan-shaped muscles that lies deep to the gluteus maximus and medius muscles.
Biceps Femoris: covers ¾ of the lateral surface of the (butt) thigh; caudal to the caudofemoralis.
Caudofemoralis: cranial to the biceps femoris.
Tensor fascia latae: largely covers the lateral aspect of the cranial portion of the vastus lateralis; next to the
sartorius and the gluteus medius.
Abductor cruris caudalis/ Tenuissimus: strongly adheres to the biceps femoris; very thin and small.
Semitendinosus: forms the caudal border of the thigh; deep to the biceps femoris; deep to the gracilis on the
ventral side.
Sartorius: extends halfway across the medial surface of the cranial aspect of the thigh (superficial)
Quadriceps femoris complex
Rectus Femoris: rests between the vastus medialis and vastus lateralis.
Vastus Lateralis: covers the cranial and lateral surface of the thigh.
Vastus Medialis: most medial of the quadriceps muscles.
Vastus Internus/ Vastus Intermedius: deep to the rectus femoris and the vastus medialis.
Iliopsoas
psoas major: largest of the muscles; medial to the iliacus.
Iliacus: most lateral and slightly dorsal of the iliopsoas.
psoas minor: occurs medial to the psoas major; characterized by its long tendon.
Gracilis: occupies the caudal half of the medial surface of the thigh (superficial).
Semimembranosus: lies on the medial aspect of the thigh; deep to the sartorius.
Adductor femoris complex: lies cranial to and partially covers the semimembranosus.
Adductor longus: cranial to the adductor femoris.
Adductor magnus et brevis
Pectineus: small muscle that lies cranial to the adductor longus; medial to the psoas.
Flexors
Triceps Surae: sometimes the gastrocnemius and the soleus are grouped to a single calf muscle.
Gastrocnemius: most of the mass of the “calf” muscle—2 heads.
Soleus: located beneath the plantaris.
Flexor Digitorum Superficialis/ Plantaris: medial, lies beneath the gastrocnemius.
Flexor Digitorum Longus: medial aspect of the shank just posterior to the tibia; long slender.
Flexor Hallucis Longus: lies lateral to the flexor digitorum longus on the posterior aspect of the shank;
proximal to the peroneus brevis.
Flexor Digitorum Brevis: lies on the plantar surface of the foot.
Tibialis Caudalis: lies beneath the flexor digitorum longus.
Popliteus: wraps obliquely around the posterior aspect of the knee from the femur to the tibia.
Calcaneus tendon (Achilles tendon)
Extensors
Tibialis Cranialis: craniolateral aspect of the tibia.
Extensor Digitorum Longus: lies beneath the tibialis cranialis along the lateral surface of the shank.
Extensor Digitorum Brevis: covers the dorsolateral surface of the tarsus and metatarsus.
Peroneus Brevis: lies posterior to the other peroneus; distal to the flexor hallucis longus.
Peroneus Longus: most superficial of the peroneus muscles; next to the extensor digitorum longus.
Peroneus Tertius: beneath the peroneus longus.
Muscles of the Head
Mylohyoid: triangular muscle that lies between the dentary bones.
Sternohyoid: slender band-like muscles that lies along either side of the mid-ventral line of the neck.
Sternothyroid: lies somewhat dorsal to the sternohyoid and lateral to the trachea.
Thyrohyoid: short, band-like muscle that lies along the lateral aspect of the larynx.
Digastric: lies along the medial ventral border of the mandible (superficial); lateral to the mylohyoid.
Stylohyoid: stretches horizontally across the posterior surface of the digastric muscle.
Geniohyoid: narrow, elongated muscle that lies medially dorsal to the mylohyoid.
Genioglossus: lies dorsolateral to the geniohyoid.
Styloglossus: lies lateral to the hyoglossus and parallel to the digastric.
Hyoglossus: lateral to the geniohyoid; rhomboidal.
Lingualis proprius
Masseter: prominently beneath and posterior to the eye; makes up the cheek region to elevate the mandible.
Temporalis: occupies the temporal fossa of the skull.