Dissection of the Superior Extremity
What is axilla?
Ans: It is a pyramidal space, situated between the upper part of the chest wall and the upper part of
the medical aspect of the arm.
Mention the steps of dissection of axilla.
Ans:
1. A curved incision along the anterior axillary fold starting from the level of the nipple and
extended laterally to the arm for about 2 1–2 inches.
2. A verticle incision from the medial end of the 1st incision downwards to the posterior exillary
fold.
3. Another vertical incision from the lateral end of the 1st incision to the posterior border of the
arm.
4. Reflect flap of the skin and the superficial fascia with fat downwards separately till the
posterior axillary fold is fully exposed.
5. Then, the deep fascia (axillary fascia) is to be reflected as that of the skin taking care not to
injure the cutaneous nerves:
a) Intercostobrachial nerve
b) Lateral cutaneous branch of the 3rd intercostal nerve
6. Remove the loose areolar tissue and fat from the axilla and clean it very cautiously without
injury to its important contents.
Mention the boundaries of axilla.
Ans:
a. Anterior wall — Pectoralis major and minor and the clavipectoral fascia.
b. Posterior wall — Subscapularis, teres major and latissimus dorsi.
c. Lateral wall — Coracobrachialis, short head of the biceps and proximal part of the humerus.
1
, d. Medial wall — Upper four ribs with their intervening intercostal muscles and upper part of the
serratus anterior.
e. Base (floor) — Axillary fascia.
f. Apex — Directed towards the root of the neck and communicates with the posterior triangle.
It is a triangular interval, bounded in front by the posterior surface of the clavicle, behind by
the superior border of the scapula and medially by the outer border of the 1st rib.
What is cervicoaxillary canal?
Ans:
It is a narrow passage formed at the apex of the axilla, through which the axillary vessels and the
cords of the brachial plexus pass from the neck to the axilla, being enveloped by the axillary sheath
derived from the deep cervical fascia.
What are the contents of axilla?
Ans:
1. Axillary artery and its branches.
2. Axillary vein and its tributaries.
3. Lower part of the brachial plexus of nerves and its infraclavicular branches.
4. Lateral cutaneous branches of the 2nd and 3rd intercostal nerves.
5. Terminal part of the cephalic vein.
6. Nerve to the serratus anterior (long thoracic nerve).
7. Axillary lymph vessels and nodes.
8. Loose areolar tissues and fat.
What is axillary artery? Mention its parts and branches.
Ans:
It is the direct continuation of the subclavian artery. It extends from the outer border of the 1st rib to
the lower border of the teres major.
2
,The pectoralis minor crosses in front of the artery and divides it into three parts—1st part above, 2nd
part behind and the 3rd part below the muscle.
Branches of the Axillary Artery:
a. From the 1st part — One
• Superior thoracic artery
b. From the 2nd part – two
• Thoracoacromial artery
• Lateral thoracic artery
c. From the 3rd part – three
• Anterior circumflex humeral artery
• Posterior circumflex humeral artery
• Subscapular artery
3
, What is axillary sheath?
Ans:
The 1st part of the axillary artery together with the axillary vein and the cords of the brachial plexus
are enveloped by a funnel shaped fibrous sheath, which is derived from the prevertebral layer of the
deep cervical fascia, called the axillary sheath. It is attached to the deep surface of the clavipectoral
fascia.
What is axillary vein? Metion its tributaries.
Ans:
Axillary vein is the continuation of the basilic vein extending from the lower border of the teres major
to the outer border of the 1st rib. It lies along the medial side of the axillary artery partly overlapping
it anteriorly.
The following nerves are placed between the axillary artery and vein —
a. Medial pectoral nerve
b. Medial cord of the brachial plexus
c. Medial cutaneous nerve of the forearm
d. Ulnar nerve
Tributaries —
a. Cephalic vein
b. Brachial veins
c. Veins corresponding to the branches of the axillary
Mention the formation, parts and branches of brachial plexus.
Ans:
The brachial plexus is the plexus of nerves formed by the ventral rami of lower four cervical and the
first thoracic (i.e., C5, C6, C7, C8, and T1) spinal nerves with little contribution from C4 to T2 spinal
nerves.
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What is axilla?
Ans: It is a pyramidal space, situated between the upper part of the chest wall and the upper part of
the medical aspect of the arm.
Mention the steps of dissection of axilla.
Ans:
1. A curved incision along the anterior axillary fold starting from the level of the nipple and
extended laterally to the arm for about 2 1–2 inches.
2. A verticle incision from the medial end of the 1st incision downwards to the posterior exillary
fold.
3. Another vertical incision from the lateral end of the 1st incision to the posterior border of the
arm.
4. Reflect flap of the skin and the superficial fascia with fat downwards separately till the
posterior axillary fold is fully exposed.
5. Then, the deep fascia (axillary fascia) is to be reflected as that of the skin taking care not to
injure the cutaneous nerves:
a) Intercostobrachial nerve
b) Lateral cutaneous branch of the 3rd intercostal nerve
6. Remove the loose areolar tissue and fat from the axilla and clean it very cautiously without
injury to its important contents.
Mention the boundaries of axilla.
Ans:
a. Anterior wall — Pectoralis major and minor and the clavipectoral fascia.
b. Posterior wall — Subscapularis, teres major and latissimus dorsi.
c. Lateral wall — Coracobrachialis, short head of the biceps and proximal part of the humerus.
1
, d. Medial wall — Upper four ribs with their intervening intercostal muscles and upper part of the
serratus anterior.
e. Base (floor) — Axillary fascia.
f. Apex — Directed towards the root of the neck and communicates with the posterior triangle.
It is a triangular interval, bounded in front by the posterior surface of the clavicle, behind by
the superior border of the scapula and medially by the outer border of the 1st rib.
What is cervicoaxillary canal?
Ans:
It is a narrow passage formed at the apex of the axilla, through which the axillary vessels and the
cords of the brachial plexus pass from the neck to the axilla, being enveloped by the axillary sheath
derived from the deep cervical fascia.
What are the contents of axilla?
Ans:
1. Axillary artery and its branches.
2. Axillary vein and its tributaries.
3. Lower part of the brachial plexus of nerves and its infraclavicular branches.
4. Lateral cutaneous branches of the 2nd and 3rd intercostal nerves.
5. Terminal part of the cephalic vein.
6. Nerve to the serratus anterior (long thoracic nerve).
7. Axillary lymph vessels and nodes.
8. Loose areolar tissues and fat.
What is axillary artery? Mention its parts and branches.
Ans:
It is the direct continuation of the subclavian artery. It extends from the outer border of the 1st rib to
the lower border of the teres major.
2
,The pectoralis minor crosses in front of the artery and divides it into three parts—1st part above, 2nd
part behind and the 3rd part below the muscle.
Branches of the Axillary Artery:
a. From the 1st part — One
• Superior thoracic artery
b. From the 2nd part – two
• Thoracoacromial artery
• Lateral thoracic artery
c. From the 3rd part – three
• Anterior circumflex humeral artery
• Posterior circumflex humeral artery
• Subscapular artery
3
, What is axillary sheath?
Ans:
The 1st part of the axillary artery together with the axillary vein and the cords of the brachial plexus
are enveloped by a funnel shaped fibrous sheath, which is derived from the prevertebral layer of the
deep cervical fascia, called the axillary sheath. It is attached to the deep surface of the clavipectoral
fascia.
What is axillary vein? Metion its tributaries.
Ans:
Axillary vein is the continuation of the basilic vein extending from the lower border of the teres major
to the outer border of the 1st rib. It lies along the medial side of the axillary artery partly overlapping
it anteriorly.
The following nerves are placed between the axillary artery and vein —
a. Medial pectoral nerve
b. Medial cord of the brachial plexus
c. Medial cutaneous nerve of the forearm
d. Ulnar nerve
Tributaries —
a. Cephalic vein
b. Brachial veins
c. Veins corresponding to the branches of the axillary
Mention the formation, parts and branches of brachial plexus.
Ans:
The brachial plexus is the plexus of nerves formed by the ventral rami of lower four cervical and the
first thoracic (i.e., C5, C6, C7, C8, and T1) spinal nerves with little contribution from C4 to T2 spinal
nerves.
4
