Class Notes (1,015,165)
CA (583,779)
Dal (3,808)
ANAT (33)
Lecture 8

ANAT 1010 Lecture 8: Lecture 8: appendicular systemPremium

11 pages36 viewsFall 2018

Department
Anatomy
Course Code
ANAT 1010
Professor
A. Jaffar
Lecture
8

This preview shows pages 1-3. to view the full 11 pages of the document.
Lecture 8: Appendicular System
The appendicular system consists of the upper and lower limbs (appendages), and its primary
function is movement.
Due to their similar developmental programs, the upper and lower limbs have much in
common, as each limb is composed of limb girdles and free limbs.
Upper Limbs: pectoral girdles + free upper limbs
Lower Limbs: pelvic girdles + free lower limbs
The first segments of the free limbs (arm in the upper limb and the thigh in the lower limb),
when compared, both have a single large bone. Proceeding distally to the second segments, the
forearm in the upper limb and the leg in the lower limb both have 2 parallel bones.
At the junctions of these second segments with the hand and the foot (wrist + ankle), there are
numerous small bones (8 in wrist; 7 in ankle), and the hands/feet have the same number and
the arrangement of bones, which form the fingers and toes.
However, the major difference between the upper and lower limbs is that the pelvic girdles of
the lower limb are firmly anchored to the vertebral column via a strong ligamentous joint.
However, the pectoral girdles of the upper limbs don’t form any joints with the vertebral
column they are instead, only weakly joined to the axial skeleton via junction of the clavicle
(collar bone) with the sternum.
Skeleton of the Upper Limb:
Each upper limb skeleton consists of 32 bones, which form 2 distinct regions:
1) The pectoral girdle:
- The term, “pectoral”, refers to the chest/breast
- The girdles attach the bones of the free upper limbs to the axial skeleton.
- Each of the 2 pectoral girdles consists of a clavicle and scapula:
You're Reading a Preview

Unlock to view full version

Subscribers Only

Only half of the first page are available for preview. Some parts have been intentionally blurred.

Subscribers Only
a. Clavicle/Collarbone: anterior bone; S-shaped”
o lies horizontally across the anterior portion of the thorax that is superior to
the first rib.
o The medial end of the clavicle (sternal end) articulates with the sternum’s
manubrium (sternoclavicular joint)
o The broad, flat, lateral end (acromial end) articulates with the scapula
(acromioclavicular joint)
o The junction of the clavicle’s two curves is its weakest point; and it is
typically smoother and straighter in females + rougher/curvier in males.
o It is subcutaneous (just under the skin; easily palpable throughout its
length).
b. Scapula/Shoulder Blade: “superior part of posterior thorax; triangular, flat bone”
o Scapula is held in place by muscle only
o A large, triangular, flat bone with a ridge on the posterior surface
You're Reading a Preview

Unlock to view full version

Subscribers Only

Only half of the first page are available for preview. Some parts have been intentionally blurred.

Subscribers Only
[POSTERIOR SURFACE OF SCAPULA]:
o A prominent ridge (spine) runs diagonally across the posterior surface of the
scapula.
o The lateral end of the scapular spine ends as the “acromion process”, a
flattened/expanded process that is felt as the high point of the shoulder.
o The acromion articulates with the acromial end of the clavicle, forming the
acromioclavicular joint.
o Inferior to the acromion is a shallow depression (glenoid cavity), which
accepts the head of the humerus (arm bone) to form the glenohumeral joint
(shoulder joint).
o Superior and inferior to the clavicle spine are two fossae: supraspinous
fossa (SURFACE OF ATTACHMENT FOR SUPRASPINATUS MUSCLES) +
infraspinous fossa (SURFACE OF ATTACHMENT FOR THE INFRASPINATUS
MUSCLES).
[ANTERIOR SURFACE OF SCAPULA]:
o On the anterior surface of the scapula is the “subscapular fossa” (slightly
hollowed out area, filled with muscle) serves as an attachment surface for
the subscapularis muscle.
o Coracoid process for muscle attachment.
You're Reading a Preview

Unlock to view full version

Subscribers Only

Loved by over 2.2 million students

Over 90% improved by at least one letter grade.