Physiologists usually need to test their scientific theories by performing experiments on living matter and, ultimately, on living organisms—animals or humans. This issue confronts the physiologist with ethical dilemmas: Can we perform physiological experiments while facing the possibly of harming living beings, or should we reject such studies, and thus preventing the good that can be derived from scientific progress?

1. Anatomy of the Limbs and the
Back- Lab 3
Rena Taher
Bachelor’s Degree in Laboratory
Medicine: An-Najah National
University/Palestine
Master’s Degree in Human Anatomy:
University of Edinburgh/United Kingdom
raltaher@najah.edu
Rena Taher

2. Lab Overview
• Introduction:
This lab talks about the brachial plexus; it discusses the major components constituting the plexus,
describes its associated nerves and terminal branches, and gives a clinical overview of the injuries
related to the plexus. This lab also illustrates the proper way of identifying the cords and terminal
branches of the brachial plexus.
• Learning Outcomes:
After studying this lecture, you should be able to:
1. Describe the formation and location of each component of the brachial plexus
2. List the branches of each component of the brachial plexus and recall its corresponding nerve
roots
3. Describe the course and function of each branch of the brachial plexus
4. Identify the M shape feature and explain how it can be used to recognise the terminal branches
of the plexus
5. Relate the symptoms associated with the brachial plexus lesions with the injured part of the
plexus
6. Identify and locate the structures that pass through the axilla.
7. Describe the formation and termination of the axillary artery and list its branches.
8. Describe the formation and termination of the axillary vein.
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3. Contents of the axilla
• Proximal parts of two muscles (the
biceps brachii and coracobrachialis
muscles)
• The axillary artery and its branches
• The axillary vein and its tributaries
• Nerves of the cords and branches of the
brachial plexus
• Lymphatic vessels and several axillary
lymph nodes
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4. Contents of the axilla
v The axillary artery begins at the
lateral border of the 1st rib as the
continuation of the subclavian artery
and ends at the inferior border of the
teres major.
v The axillary artery is divided into
three parts relative to the pectoralis
minor (the part number also indicates
the number of its branches).
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5. Contents of the axilla
v The axillary vein is formed
by the union of the brachial
veins and the basilic vein at
the inferior border of the
teres major.
v The axillary vein ends at the
lateral border of the 1st rib,
where it becomes the
subclavian vein.
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6. The brachial plexus
v The brachial plexus is a major
network of nerves supplying the
upper limb.
v The brachial plexus is formed
by the union of the anterior
(ventral) rami of the C5–T1
nerves.
v The plexus can be easily
identified as it wraps around the
axillary artery that supplies the
upper limb.
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7. Components of the brachial plexus
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8. Structure of the brachial plexus
v The anterior rami
of the C5–T1
nerves constitute
the roots of
brachial plexus.
v Branches of the
roots: DS & LT
nerves.
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9. Structure of the brachial plexus
• Superior trunk (C5 +
C6 roots): gives the
Suprascapular nerve &
nerve to Subclavius.
• Middle trunk (C7 root)
• Inferior trunk (C8 and
T1 roots)
v Each trunk of the
brachial plexus divides
into anterior and
posterior divisions.
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10. Structure of the brachial plexus
• Lateral cord (anterior
divisions of the
superior and middle
trunks): 3 nerves.
• Medial cord (anterior
division of the inferior
trunk): 5 nerves.
• Posterior cord
(posterior divisions of
all three trunks): 5
nerves (STARS).
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11. Structure of the brachial plexus
• Lateral cord (anterior
divisions of the
superior and middle
trunks): 3 nerves.
• Medial cord (anterior
division of the inferior
trunk): 5 nerves.
• Posterior cord
(posterior divisions of
all three trunks): 5
nerves (STARS).
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12. Structure of the brachial plexus
(C5)
(C5-C7)
(C5, C6)
(C5, C6)
(C5-C7)
(C5-C7)
(C8-T1)
(C8-T1)
(C8-T1)
(C5), C6-Tl
(C7), C8,Tl
(C5, C6)
(C6-C8)
(C5, C6)
(C5, C6)
C5-C8, (Tl)
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13. Structure of the brachial plexus: the M shape
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14. Brachial plexus: Dissection vs Schematic
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15. Rena Taher
Draw it to know it

16. The arm
v The arm extends from the shoulder to
the elbow.
Ø Bones: humerus, radius & ulna
(proximal ends).
Ø Muscles:
• The anterior compartment of the arm
contains muscles that predominantly
flex the elbow joint.
• The posterior compartment contains
muscles that extend the elbow joint.
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17. Bones of the arm: Humerus
Anterior view Posterior view
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18. Bones of the arm: radius & ulna
Anterior view
Posterior view
Anterior view, proximal end of radius
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