Appendicular Skeleton Concepts

Question 1

Contrast the location of the Appendicular skeleton with the Axial.

Answer 1

The appendicular skeleton is the bones that make up the limbs of the body and the bones that connect the limbs to the axial bones. They function to help the body move. The axial skeleton is the bones that sit on the midline of the body and are hematopoietic. They function by protecting the body’s internal organs.

Question 2

Count out the 126 bones of the Appendicular skeleton, and account for their locations

Answer 2

2 in each shoulder girdle (4)
2 in the pelvic girdle (2)
30 in each upper limb (60)
30 in each lower limb (60)

Question 3

Identify the bones of the pectoral (shoulder) girdle, their functions, and their principal markings. Use our 5 categories – Regions (R), Non-articular projections (NAP), Articular projections (AP), Non-articular depressions (NAD), and articular depressions (AD) to navigate.

Answer 3

r= superior, medial, and lateral borders
nap= posterior spine, divides supraspinous vs infraspinous
ap= acromion process, articulates with the lateral edge of the clavicle
nad= subscapular fossa, attach muscle
ad= glenoid cavity, socket that receives the head of the humerus in the glenohumeral joint

Question 4

highlight the bones/bony landmarks involved in the elbow joint.

Answer 4

Humero-ulnar (medial)= trochlea notch of the ulna receives the trochlea of the humerus when the elbow is flexed
humero-radial (lateral)=head of the radius fits into the radial fossa of the humerus when the elbow is flexed
humero-ulnar(posterior)olecranon of the ulna fits into the olecranal fossa of the humerus when the elbow is extended

Question 5

Classify the bones of the forearm: which is medial and which is lateral, which articulates with the carpal bones

Answer 5

• Radius is lateral, widens distally
• Ulna is medial, widens proximally into the olecranon (distal head)
• Only the radius bone articulates with the carpal bones
• 2 articulations of the radius with 2 carpal bones form the radiocarpal joint
• Articulation for the scaphoid and articulation for the lunate

Question 6

name the 8 carpal bones and organize them into two rows, proximal and distal

Answer 6

Proximal:
Scaphoid, Lunate, Triquetrum, Pisiform

Distal:
Trapezium, Trapezoid, Capitate, Hamate

Question 7

Detail the 19 metacarpal & phalangeal bones of each hand, just accounting for how you come up with a total of 19.

Answer 7

5 metacarpals(hand bones):
Numbered from 1-5 laterally to medially

14 phalanges:
All long bones with base, shaft, and head(proximally to distally) except the pollex with only 2

Question 8

Identify the bones of the pelvic girdle and the bones/bony landmarks involved in the hip joint

Answer 8

The pelvic girl is made of two coxal bones, each bone consists of 3 bones that fuse together superiorly to inferiorly: ilium, ischium, and pubis

The head of the femur articulates with the acetabulum of the pelvis to form the hip joint.

Question 9

Compare the principal differences between the female and male pelvis.

Answer 9

Male Pelvis:
- Larger, heavier, more narrow in width
- Smaller inlet (heart-shaped) and outlet
- Has pubic arch angle of less than 90degrees

Female Pelvis
- Wider, has flared iliac crest
- Pelvic inlet wider and more oval shaped
- Pubic arch angle of more than 90degress
- More moveable pubic symphysis and more flexible coccyx

Question 10

Explain how the arcuate/pectineal lines delineate the true pelvis (inferiorly) from the false pelvis superiorly (the abdominal cavity!)

Answer 10

The false pelvis is above the pectineal lines and the true pelvis is below the pectineal lines

Question 11

Identify the bones of the lower limb

Answer 11

Femur and patella (2)
Tibia and fibula (2)
Tarsals (7)
Metatarsals (5)
Phalanges (14)

Question 12

Identify the bones/bony landmarks that make up the knee and ankle joints.

Answer 12

Knee joint= lateral and medial condyles of the tibia articulate with medial and lateral condyles of the femur
Ankle joint= Distally, the medial malleolus of the tibia articulates with the talus to form the medial part of the ankle joint. The superior part of the talus articulates laterally with the lateral malleolus of the fibula

Question 13

Detail the metatarsals

Answer 13

There are five metatarsal bones in each foot, which are numbered 1 to 5, starting
from the big toe. The metatarsals are long bones that form the arch of the foot and
provide support for the body’s weight. They are located between the tarsal bones
and the phalanges. The length of each metatarsal bone varies, with the first
metatarsal being the shortest and the second metatarsal being the longest.

Question 14

Detail the phalanges

Answer 14

There are fourteen phalanges bones in each foot, which are divided into three
groups: the proximal phalanges, the middle phalanges, and the distal phalanges.
The phalanges bones are also numbered 1 to 5, starting from the big toe, and each
toe has three phalanges, except for the big toe, which only has two.

Proximal phalanges: These are the largest of the phalanges and are located closest to the metatarsal bones. There are five proximal phalanges bones in each foot.

Middle phalanges: These are smaller than the proximal phalanges and are located in the middle of the toe. There are four middle phalanges bones in each foot, except for the big toe, which does not have a middle phalanx.

Distal phalanges: These are the smallest of the phalanges and are located at the tip of the toe. There are five distal phalanges bones in each foot.

Question 15

contrast a non-articular projection with an articular projection USING THE SAME STRUCTURE!! Like the acromion process.

Answer 15

The acromion process is where ligaments and muscles, notably the deltoid muscle, attach. The articular component of the acromion process, on the other hand, forms an articulation with the clavicle bone to form the acromioclavicular joint. This joint provides for shoulder movement and contributes to the stability of the shoulder.

Question 16

compare something like fossae, which can be used as non-articular depressions (scapula) with fossae used as articular depressions (in the humerus).

Answer 16

The fossae on the scapular, the subscapular fossa, the supraspinous fossa, and infraspinous fossa, are non-articular, serving as attachment points for muscles and ligaments. The fossae on the humerus, however, serve as sites of articulation for the elbow joint. Anteriorly, the radial fossa of the humerus receives the head of the radius, and the coronoid fossa of the humerus receives the coronoid process of the ulna when the arm is flexed. Posteriorly, the olecranon fossa of the humerus receives the olecranon of the ulna when the arm is fully extended.

Question 17

Describe fibrous joints by structure (give one synarthrotic and amphioarthrotic example)

Answer 17

• lack of cartilage and synovial cavity
• Little to no movement
• Held by dense irregular C.T

Synarthrotic example: sutures
Amphiarthrotic example: interosseous membranes

Question 18

Describe cartilaginous joints by structure (give one synarthrotic and amphioarthrotic example)

Answer 18

• bar of cartilage between two bones
• Lack of synovial cavity and little to no movement

Synarthrotic example: epiphyseal plate
Amphiarthrotic example: pubic symphysis

Question 19

Describe synovial joints BY STRUCTURE

Answer 19

• ligaments hold bones together to form a synovial cavity and a freely moveable joint
• Two layered capsules enclose the cavity: outer fibrous and inner synovial membrane

Question 20

What is the difference between diarthrotic and syarthrotic/amphiarthrotic

Answer 20

synarthrosis= no movement
amphiarthrosis= slight movement
diarthosis= allow lots of types of movement

Question 21

Contrast gliding movement with the more complex suite of movements

Answer 21

Gliding movements are simple back-and-forth and side-to-side movements. They are limited in range and have no significant alternations of the angle between bones.

Complex suit movements increase or decrease the angle between articulating bones.

Question 22

Contrast flexion, extension, and hyperextension, relative to the anatomical plane.

Answer 22

flexion= decrease in the angle (bending elbow), on the midsagittal plane
extension=an increase in the angle (straight arm), on the midsagittal plane
hyperextenson= continuation of extension beyond the normal extension(craning head to look up), on mid-sagittal plane

Question 23

Relate typically flexion to the sagittal plane while identifying and describing a couple of body flexions that DO NOT occur in the sagittal plane

Answer 23

Flexing the arm at the elbow relates to the sagittal plane. Flexion of the thumb does not occur on the sagittal plane, it occurs on the frontal. Lateral flexion occurs on the frontal plane

Question 24

Contrast the midlines of abductions of the phalanges, to midlines of traditional abductions of the body.

Answer 24

The middle finger acts as the midline for the abductions of the phalanges. Traditional abductions of the body are subject to the normal anatomical position midline.

Question 25

Focusing on JUST THE GLENOHUMERAL JOINT, identify some of the key structures in the joint, their locations, and their roles.

Answer 25

The glenohumeral joint is a ball and socket joint that connects the humerus bone to
the scapula.

Glenoid Labrum= narrow rim of fibrocartilage that surrounds the glenoid cavity, widening it.

Coracohumeral ligament= connects the posterior portion of the coracoid process of the scapula to the greater tubercle of the humerus. This strengthens the superior and anterior part of the articular capsule

Glenohumeral ligaments= extend from the glenoid cavity to the lesser tubercle and anatomical neck of the humerus

Capsular ligament= thickening of the articular capsule

Subacromial bursa= superiorly, sits inferior to the acromion to cushion and reduce friction during abduction of the arm

Subscapular busa= anteriorly, sits superficial to the subscapular muscle, cushioning and reducing friction with the pectoralis major and minor muscles that lie superficial to the bursa when moving across the shoulder joint