Cat Dissection Checkpoints 1-3: Location & Function Flashcards
Location & Function
Masseter
Inferior and posterior to the eye, occupies much of the cheek area of the face
Elevation of the mandible
Location & Function
Mylohyoid
Small, thin muscle with fibers that extend trasversely across the two dentery bones of the mandible. Right and left mylohyoid are separated by a thin line of fascia (called the median raphe)
Elevates the floor of the mouth
Location & Function
Sternohyoid
Slender muscle extending along the midventral line of the neck
Retracts the hyoid bone
Location & Function
Cleidomastoid
Flat muscle located dorsolateral to the sternomastoid
Rotates the head when clavicle is held stationary and moves the clavicle cranially when the head is held stationary
Location & Function
Digastric
Thick muscle extending along the ventral border of the mandible
Depresses the mandible
Location & Function
Sternomastoid
V-shaped muscle on the ventral side of the neck
Simultaneous contraction results in flexing of the head, individual contraction rotates the head
Location & Function
Clavotrapezius
Flat, wide muscle. Covers much of the lateral aspect of the night.
Forward extension of the humerus
Location & Function
Clavobrachialis
Continuation of clavotrapezius into the forelimb (also called clavodeltoid)
Flexes the forearms, or antebrachium (no equivalent muscle in humans).
Location & Function
Spinodeltoid
Flat, band-shaped muscle ventral to the acromiotrapezius and levator scapulae ventralis, and caudal to the acromiodeltoid.
Synergist with the acromiodeltoid to flex and rotate the humerus.
Location & Function
Acromiotrapezius
Very thin, trapezoid-shaped muscle of the cranial back.
Adducts the scapula. Represented by the central portion of the trapezius in the human
Location & Function
Spinotrapezius
Triangle-shaped muscle that forms the caudal third of the trapezius group in the cat, with a caudodorsal border to the latissimus dorsi.
Pulls the scapula caudally. Represented by inferior portion of the trapezius in the human.
Location & Function
Latissimus Dorsi
Large, flat muscle on the back that is located immediately caudal to (and slightly covered by) the spinotrapezius.
Pulls the forelimb dorsocaudally
Location & Function
Pectoralis Major
Superficial and deep portions. Superficial portion is a thin, flat muscle similar in width to pectoantebrachialis and partially deep to it. Extends from midventral line and manubrium to the shaft of the humerus. Deep portion is located beneath the superficial and is thicker and wider.
Adduction of the forelimb (for both portions)
Location & Function
Pectoralis Minor
Thick, fan-shaped muscle that extends beneath and caudally to the deep portion of pectoralis major
Adduction of the forelimb
Location & Function
Pectoantebrachialis
Most superficial muscle of the chest. Extends from the midline of the body to the proximal end of the humerus
Adduction of the forelimb. Not found in humans.
Location & Function
Xiphihumeralis
On caudal border of pectoralis minor. Long, thin muscle extending from the xiphoid process to the ventral border of the humuerus.
Functions as a synergist with the pectoralis muscles in the adduction of the forelimb. Xiphihumeralis is absent in humans.
Location & Function
Supraspinatus
Thick muscle that lies within the supraspinous fossa of the scapula
Protracts the humerus
Location & Function
Infraspinatus
Slightly smaller than supraspinatus. Occupies infraspinous fossa of the scapula
Rotation of the humerus in a lateral direction
Location & Function
Triceps Brachii - Long Head
The axillary border of the scapula near the glenoid fossa
Extension of the antebrachium
Location & Function
Triceps Brachii - Lateral Head
Deltoid ridge of the humerus
Extension of the antebrachium
Location & Function
Biceps Brachii
Large, thick muscle located on the cranial surface of the humerus
Primary flexor of the antebrachium, supinates the manus, and stabilizes the shoulder joint. Human biceps brachii includes two heads of origin, the short and long heads.
Location & Function
Brachialis
Small muscle on the craniolateral surface of the humerus, partially obscured by the lateral head of the triceps
Synergist with the biceps brachii for flexion of the antebrachium
Location & Function
Acromiodeltoid
Flat muscle located immediately ventral to the levator scapulae ventralis and caudal to the clavobrachialis
Synergist with spinodeltoid for flexion and lateral rotation of the humerus. Not a distinct muscle in humans, instead contributing with the clavobrachialis and spinodeltoid to form the large deltoid on the front of the shoulder
Location & Function
Levator Scapulae Ventralis
A band-like muscle lying between the clavotrapezius and the acromiotrapezius
Elevation and rotation of the scapula
Location & Function
Subscapularis
Large, triangle-shaped muscle that occupies the subscapular fossa of the scapula
Adducts the humerus
Location & Function
Palmaris Longus
Arising from two heads of origin on the ventral side of the antebrachium
Flexes the digits. In humans, the palmaris longus is the equivalent muscle to the deep head of the flexor digitorum superficialis in the cat
Location & Function
Flexor Carpi Ulnaris
Muscle with two heads of origin on the ventral side of the antebrachium
Flexion of the carpus
Location & Function
Extensor Carpi Ulnaris
Long, narrow muscle that extends along the ulnar side of the antebrachium
Extends the carpals on the ulnar side
Location & Function
Extensor Digitorum Lateralis
Long, narrow muscle of the dorsal antebrachium lateral to the extensor digitorum communis
Extends the digits of the manus. Does not exist in humans, is replaced by the extensor digitii minimi.
Location & Function
Extensor Digitorum Communis
Long, narrow muscle of the dorsal antebrachium that partially overlaps the extensor carpi radialis longus and brevis
Extension of the second to fifth digits of the manus. Human muscle is similar, but is called the extensor digitorum
Location & Function
Extensor Carpi Radialis Longus
Narrow muscle dorsal to the brachioradialis on the radial side of the antebrachium
Supination of the manus
