OF THE HEAD, TRUNKAND ARMS
(clavobrachialis in the cat)
(Page numbers refer to Pictorial Anatomy of the Cat, rvsd, by Gilbert.)
We will be studying head and trunk muscles of the cat, most of which are analogous to those in the human. Working with a skinned cat ( see previous protocol ) remove cutaneous muscle layer (allows cat to twitch its skin) and a white layer of superficial fascia to better see muscle fiber directions and make the muscles more apparent. Carefully outline, separate and lift the muscles by use of a blunt probe. If the structure in question has multiple fibers in it, it is muscle. Look for intersections between fiber directions, this often indicates two muscles. Fingers are the best blunt probes...
When you need to cut separated
muscles to see deep muscles, the superficial muscle to be reflected
be snipped midway between insertion and origin, and laid back to its
and insertion, noting where they are located. Make four illustrations:
1) ventral thorax, upper appendage and abdomen, superficial
2) Ventral thorax and upper appendage, deep
(back) deep and dorsal superficial
4) Second illustration of the deep dorsal muscles.
I. VENTRAL NECK, CHEST AND ABDOMEN:
|(See Gilbert, p. 18)|
|Undissected chest. Remove as much adipose tissue and
you can so that the fibers of the muscles can be seen.
Can you find the pectoantebracialis, pectoralis major, latissimus dorsi and triceps brachii?
Here is the same image with the chest muscles labeled.
separated from the underlying pectoralis major, and is being lifted in
The deltoid (called
in the cat) has been freed from unterlying tissues.
|Lift deltoid and pectoantebrachialis as a unit and cut and reflect.|
Origin: upper sternum.
Insertion: proximal 2/3 of humerus between the biceps and brachialis
|pectoralis minor||The pectoralis major has been
and pectoralis minor is being lifted by the probe.
In humans, pectoralis originates from ribs and inserts in the coracoid process of scapula.
|The superficial-most muscle of
surface of the arm is the epitrochlearis. It has no
in humans. It must be cut and reflected to see the underlying
brachii and biceps brachii.
|retinaculum||transverse carpal ligament on cat, holds down tendons of insertion|
2. Separate pectoralis major from
minor, cut both, reflect to see: (Gilbert p. 24)
|subscapularis||With the pectoralis major and
and reflected, the scapula will fall away from the chest to reveal the
subscapularis on its underside.
|teres major||closest to axillary border of
|serratus anterior||(serratus ventralis in the cat)
3. Identify the external muscles of
the abdomen (p. 24)
|external oblique||superficial most muscle of the abdomenal wall|
|rectus abdominis||anterior most muscle of abdomen|
II. BACK: (p. 22) Caution: the trapezius is very thin and easily torn when outlining it with the probe. Remove cutaneous muscle layer, note the boundary between trapezoid and the latissimus dorsi which plunges below it.
1. Lift trapezius from underlying
|trapezius||called acromio- and spinotrapezius in the cat|
|latissimus dorsi||fr. spine of lower back to medial humerus|
2. Cut and reflect trapezius to see
muscles related to or on the scapula: (p. 25). Here is a labeled
view of the deep muscles of the back and scapula.
|infraspinatus||muscle of the glenohumoral joint, lies below spine of scapula|
|supraspinatus||muscle of the glenohumoral joint, lies above spine of scapula|
|teres major||muscle of the glenohumoral joint, inserts ant. surf. humerus|
|teres minor||muscle of the glenohumoral joint, inserts post. surf. humerus|
|levator scapulae||superior to rhomboideus muscles|
|rhomboideus & r. capitis||from spine and skull to vertebral border of scapula|
(to the left and below the tip of the probe)
|Seen below the rhomboideus
The "bandage" muscle in the posterior neck.
Origin: upper thoracic spinous
Send Email to: FANKHADB@UC.EDU
Brachial plexus: To be studied Winter Quarter:
deltoid and cutting the latissimus dorsi so that it can be
Cutting the pectoralis. The trapezius has been cut and reflected to
show the scapula and rhomboideuses