DISSECTION PHOTOS- Forelimb Flashcards
Identify different structures from real-life dissection images. (19 cards)
In the axiallary region, identify the biceps brachii:
m. biceps brachii
In the dog, the m. biceps brachii has only one head. Its tendon of origin (sometimes called the bicipital tendon) lies in the intertubercular groove of the humerus, surrounded by an extension of the shoulder joint capsule. At the distal extremity, the muscle splits into two distinct tendons of insertion.
O: supraglenoid tubercle of the scapula
I: ulnar and radial tuberosities
A: elbow flexion, shoulder extension
N: musculocutaneous n.
In the axiallary region, identify the brachiocephalicus muscle:
m. brachiocephalicus
The m. brachiocephalicus is divided by an indistinct clavicular intersection, the tendinous remnant of the clavicle, into the m. cleidocephalicus (extending from the tendon to the head) and the m. cleidobrachialis (extending from the tendon to the arm). In dogs, the m. cleidocephalicus has two distinct muscle bellies, one inserting on the neck (pars cervicalis), visible here, and one on the skull (pars mastoideus).
Attachments: dorsal median raphe of neck & mastoid process of skull (m. cleidocephalicus); cranial aspect of distal humerus (m. cleidobrachialis)
A: Advance limb, extend shoulder, laterally flex neck
N: Cervical spinal nn., accessory n.
In the axiallary region, identify the clavicular intersection of the brachiocephalicus muscle:
The m. brachiocephalicus is a long muscle bridging between the brachium and the head. It is divided by a more-or-less distinct clavicular intersection (tendon), the connective tissue remnant of the clavicle, into the m. cleidocephalicus (extending from the intersection to the head and the m. cleidobrachialis (extending from the intersection to the arm).
In the axiallary region, identify the cleidobrachialis portion of the brachiocephalicus muscle:
m. cleidobrachialis
The m. brachiocephalicus is a long muscle bridging between the brachium and the head. It is divided by a more-or-less distinct clavicular intersection (tendon), the connective tissue remnant of the clavicle, into the m. cleidocephalicus (extending from the intersection to the head and the m. cleidobrachialis (extending from the intersection to the arm).
In the axiallary region, identify the cleidocephalicus portion of the brachiocephalicus muscle:
m. cleidocephalicus
In dogs, the m. cleidocephalicus has two distinct muscle bellies, one inserting on the neck (pars cervicalis) and one on the skull (pars mastoideus). Pars cervicalis is a fan-shaped strap muscle; pars mastoideus takes origin at the clavicular intersection with it, but becomes identifiable as a thicker, separate portion at midneck, running deep to the cranial edge of the cervical portion.
O: clavicular intersection
I: dorsal median raphe of neck (pars cervicalis) and mastoid process of skull (pars mastoideus)
A: advance limb, extend shoulder, lateral flexion of neck (unilateral action) or fixation of neck (bilateral action)
N: ventral brr. of cervical spinal nn., accessory n.
In the axiallary region, identify the acromial part of the deltoid muscle (pars acromialis):
m. deltoideus, pars acromialis
(deltoid m., acromial part)
The m. deltoideus has two heads, pars scapularis and pars acromialis.
O: spine and acromial process of scapula
I: deltoid tuberosity of humerus
A: flexion of shoulder joint
N: axillary n.
In the axiallary region, identify the latissimus dorsi muscle:
m. latissimus dorsi
O: thoracolumbar fascia
I: via an aponeurosis to the tendon of the m. teres major and m. pectoralis profundus.
A: adduct limb, draw limb caudad, flex shoulder; when limb is fixed in weight-bearing, draws the trunk forward
N: thoracodorsal n. (C7-8, T1)
In the axiallary region, identify the external abdominal oblique muscle (obliquus externus abdominis):
m. obliquus externus abdominis
(external abdominal oblique m.)
The broad m. obliquus externus abdominis is a superficial sheet-like muscle that covers most of the abdomen and the ventral part of the thorax as far craniad as the fourth or fifth rib. The muscle is sometimes divided into a pars costalis and a pars lumbalis, the names reflecting the origin of the fibers, which run ventrocaudad. It is distinguished by the marked proportion of fibrous tissue in its attachments, reflecting its important role in support of the weight of the abdominal organs. The muscle inserts on the midline of the abdomen (the linea alba) via a broad aponeurosis which forms part of the external lamina of the rectus sheath. Caudally, its aponeurosis blends into the insertion of the m. rectus abdominis on the cranial edge of the pelvis (the prepubic tendon).
O: pars costalis—middle parts of 4/5th rib through 12th rib
pars lumbalis—13th rib and thoracolumbar fascia
I: linea alba, prepubic tendon
A: compression of abdominal cavity, flexion of vertebral column, lateral flexion of vertebral column when acting unilaterally
N: lateral brr of spinal nerves C5/6 through L3
In the axiallary region, identify the deep pectorialis muscle:
m. pectoralis profundus
(deep pectoral m.)
O: sternum and median raphe
I: lesser and greater tubercles of humerus, medial brachial fascia
A: draw limb caudad, extend shoulder (can flex shoulder when limb not weight-bearing)
N: caudal pectoral nn. (C8, T1)
In the axiallary region, identify the sternocephalicus muscle:
The m. sternocephalicus has two distinct muscle bellies. The occipital part is broad and flat, and the mastoid part is round in cross-section.
O: manubrium sterni
I: pars occipitalis: nuchal crest in the occipital region. pars mastoideus: mastoid process of the temporal bone.
A: draw head and neck to side.
N: branches from accessory nerve and ventral branches of cervical nerves.
In the axiallary region, identify the triceps brachi:
m. triceps brachii
In the dog, the m. triceps brachii possesses four heads. These insert in common via a stout tendon on the point of the elbow, formed by the olecranon of the ulna. There is a synovial bursa between the tendon of the long head and the cranial part of the olecranon.
O: long head: caudal border of scapula; lateral head: tricipital line of humerus; accessory head: neck of humerus; medial head: crest of lesser tubercle
I: olecranon
A: shoulder flexion (long head only) and extension of elbow
N: radial n.
In the axiallary region, identify the superficial pectoral muscles:
mm. pectorales superficiales
(superficial pectoral mm.)
The superficial pectoral muscles comprise descending and transverse parts.
O: cranial sternum to about the 3rd costal cartilage
I: cranial edge of humerus on a line running distad from the greater tubercle to about the midpoint of the bone
A: adduction of limb; advancement or retraction of the limb, depending on starting position and whether or not the limb is weight-bearing
N: cranial pectoral nn., cervical nn. 7 & 8
In the axiallary region, identify the descending portion of the superficial pectoral muscles:
mm. pectorales superficiales
(superficial pectoral mm.)
The superficial pectoral muscles comprise descending and transverse parts.
O: cranial sternum to about the 3rd costal cartilage
I: cranial edge of humerus on a line running distad from the greater tubercle to about the midpoint of the bone
A: adduction of limb; advancement or retraction of the limb, depending on starting position and whether or not the limb is weight-bearing
N: cranial pectoral nn., cervical nn. 7 & 8
In the axiallary region, identify the transverse portion of the superficial pectoral muscles:
mm. pectorales superficiales
(superficial pectoral mm.)
The superficial pectoral muscles comprise descending and transverse parts.
O: cranial sternum to about the 3rd costal cartilage
I: cranial edge of humerus on a line running distad from the greater tubercle to about the midpoint of the bone
A: adduction of limb; advancement or retraction of the limb, depending on starting position and whether or not the limb is weight-bearing
N: cranial pectoral nn., cervical nn. 7 & 8
In the axiallary region, identify the axillobrachial vein:
.
axillobrachial v.
The cephalic vein is continued proximally by the axillobrachial vein, which is identifiable superficially where it crosses the lateral head of the m. triceps brachii near the shoulder joint. It then passes deep to the m. deltoideus and continues mediad past the caudal aspect of the shoulder joint to join the axillary vein. It receives venous blood not only from the cephalic vein but also from the triceps muscle.
In the axiallary region, identify the brachial vein:
brachial v.
The brachial vein receives smaller veins of antebrachium, including the conjoined median and median cubital vv. It ascends the medial aspect of the brachium, caudal to the brachial a., and receiving other satellite veins of the brachium.
In the axiallary region, identify the cephalic vein:
The cephalic v. receives venous blood from the distal thoracic limb. It lies on the cranial aspect of the antebrachium where it is a preferred site for collection of blood and placement of intravenous catheters. The cephalic gives off a medially directed branch on the flexor surface of the elbow, the median cubital v., which makes an anastomotic connection with the brachial v. on the medial aspect of the limb. The continuation of the cephalic v. flows deep to the m. cleidobrachialis at mid-brachium to join the external jugular v. at the thoracic inlet.
In the axiallary region, identify the external jugular vein:
The external jugular vein in the jugular furrow of the neck receives venous blood from the head, neck and thoracic limb. Inside the thoracic inlet, it joins the subclavian vein to become the brachiocephalic vein. The external jugular vein is a preferred site for venipuncture and placement of intravenous catheters in dogs.
In the axiallary region, identify the omobrachial vein:
omobrachial v.
The omobrachial vein makes an anastomotic connection between the axillobrachial and external jugular veins. It can be seen crossing superficially over the acromial part of the m. deltoideus and the m. cleidocephalicus.
