|
Shoulder
Brachium
Antebrachium
Facial
and Masticatory Muscles
Thorax
and Heart
Brain
Body
Wall
Hip
and Thigh
Shank
and Foot
Digestive
System
Urinary
and Reproductive Systems
Hip
and Tail
|
 Brachium
of the Rat (Rattus norvegicus)
Photos and text by Yu Jin Kim and Ana Panduro
General overview:
Rattus norvegicus is a quadruped and
it can pronate and supinate its forelimb although these motions are very
limited. Its forelimbs are short compared to body length but the muscles
of its forelimbs are very well developed for its locomotion and for holding
food.
Dissection:
Dissection of the brachium was relatively easy
because the muscles were not attached to the skin which made dissecting
some other areas very difficult. However, the upper arm of Rattus
norvegicus is very small and careful dissection was necessary to avoid
breaking the muscles. During the course of dissection, muscles of the
brachium were identified.
Elbow Extensors:
| muscle |
origin
|
insertion
|
action
|
|
tensor fasciae
antebrachii
|
tendon of
insertion of the latissimus dorsi muscle
|
olecranon,
antebrachial fasia
|
extension
of the elbow, tensing of the antebrachial fascia
|
|
triceps
|
|
|
|
|
a. long head
|
caudal (axillary)
border of scapula
|
olecranon
process of ulna
|
extension
of elbow, flexion of shoulder, pronation of antebrachium
|
|
b. lateral
head
|
greater tubercle
and neck of humerus
|
olecranon
process of ulna
|
extension
of elbow, flexion of shoulder, pronation of antebrachium
|
|
c. medial
head
|
medial, proximal
side of the humeral neck
|
olecranon
process of ulna
|
extension
of elbow, flexion of shoulder
|
|
d. anconeus
|
condyles of
humerus
|
olecranon
process of ulna
|
extension
of the elbow, tenses the antebrachial fascia
|
Elbow
Flexors:
| muscle |
origin
|
insertion
|
action
|
|
brachialis
|
caudal neck
of humerus
|
medially distal
to the coronoid process of the ulna
|
flexion of
the elbow joint
|
|
biceps brachii
|
|
|
|
|
a. short head
|
coracoid process of the scapula
|
radial tuberosity
|
flexion of elbow, extension of shoulder
|
|
b. long head
|
tendon of supraglenoid tuberosity of
scapula
|
radial tuberosity
|
flexion of elbow, extension of shoulder
|
|
coracobrachialis
|
coracoid process of the scapula, short
head of biceps
|
medial humerus
|
extension of shoulder
|
|
