MY NOTES DO NOT REPLACE THE LAB MANUAL. LAB MANUAL IS YOUR PRIMARY RESOURCE. YOU ARE RESPONSIBLE FOR KNOWING THE MATERIAL FROM CORRESPONDING CHAPTER(S) IN THE LAB MANUAL AND CLASS HANDOUT(S)!!!

 

THIS CHAPTER CONTAINS A LOT OF TERMINOLOGY, NOT ALL OF WHICH WILL BE COVERFED IN THE LAB COURSE; HOWEVER IN YOUR LECTURE COURSE YOUR PROFESSOR WILL COVER EVERYTHING. 

!!!MAKE SURE TO LOOK OVER ALL OF THE TERMS!!!

 

Chapter 11:  The Appendicular Skeleton

           

Appendicular Skeleton:  composed of 126 bones: 64 bones in the appendages and the pectoral girdle (shoulders and upper limbs) 62 in the pelvic girdle pelvis and lower limbs.

Bones of the Pectoral Girdle and Upper Extremity

            The Pectoral (Shoulder) Girdle

Function:  1.  Attachment of the upper limbs to the axial skeleton

                  2.  Attachment points for many trunk and neck muscles.

1.  Clavicle/ collarbone – sternal end attaches to sternal manubrium(Figure 11.2, p147)

Acromial end - articulates with scapula.  Holds arm away from the top of the thorax.

 

2.      Scapulae/ shoulder blades – has no directs attachment to the axial skeleton but is loosely held in place by the trunk muscles. (Figure 11.2, p147)

                                    A.  Spine - deltoid muscle attachment

B.  Acromion process – connects with the clavicle.

                                    C.  Coracoid process – serves as attachment point for some of the upper limb muscles.

                                    D.  Glenoid cavity – a shallow socket that receives the head of the arm bone – humerus.

           

 

The Arm

                        Humerus – long bone. (Figure 11.3, p148)

                                    Head – fits into the shallow glenoid cavity of the scapula

                                    Greater and lesser tubercles - attachemnt for biceps muscles

 

            The Forearm (Figure 11.4, page 149)

                        Radius - lateral bone of the forearm

                        Ulna - medial bone of the forearm

                                    Radial notch – articulates with the head of the radius.

 

 

 

            The Hand – manus (Figure 11.5, page 150)

                        Three groups of bones:

                                    1.  Carpus – wrist.  8 carpal bones

2.  Metacarpals – palm.  Numbered 1 to 5 from the thumb.  

3.  Phalanges – fingers.  Numbered 1 to 5 from the thumb.  14 bones.  Each finger contains three phalanges except for the thumb which has only two.

 

 

Bones of the Pelvic Girdle and Lower Limb 

 

        The Pelvic (Hip) Girdle (Figure 11.6, pages 151)

                        Formed by two coxal bones (2 fused bones).  Bones are heavy and massive, and attach securely to the axial skeleton.  The sockets for the heads of the femurs (thigh bones) are deep and heavily reinforced by ligaments to ensure a stable, strong attachment.  The ability to bear weight is more

important than mobility and flexibility.  Combined weight of the upper body rests on the pelvis. 

                        Each coxal bone is a result of the fusion of three bones:

                                    1.  Ilium – large flaring bone. 

                                    2.  Ischium – “sit – down” bone.

                                    3.  Pubis - anterior poertion of the coxal bone.

                        All three bones fuse at the deep hemispherical socket – acetabulum, which receives the head of the thigh bone.

 

 

           

        Comparison of the Male and Female Pelves.  (Table 11.1, page 153)

Bones of males are usually larger, heavier, and have more prominent bone markings.  The female pelvis reflects modifications for childbearing – wider, shallower, lighter, and rounder to support the increasing size of a fetus, and to allow the infant’s head to descend through the birth canal. 

        The Thigh (Figure 11.7, page 154)

                        Femur – thigh bone.  Heaviest, strongest bone in the body.

                                    Head – articulates with the hip bone via acetabulum.

                                    Greater and lesser trochanters – sites for muscle attachment.

                        Patella – enclosed in the tendon of the quadriceps, that secures anterior thigh muscles to the tibia.  Guards the knee joint, and improves the leverage of the thigh muscles acting across the knee joints.

           

The Leg (Figure 11.8, page 155)

            Tibia - larger & medial bone

            Fibula - parallel to the tibia

 

The Foot (Figure 11.9, page 156)

            7 tarsal bones, 5 metatarsals (instep), 14 phalanges (toes)

                        Body weight is concentrated on two largest tarsals

Calcaneus  - heel bone

Talus – b/n tibia and calcaneus

                        Each toe has three phalanges except the great toe, which has two.     

 

The Arches

            The foot has two important functions: weight bearing and propulsion. These functions require a high degree of stability and flexibility.

            The foot has three arches. The medial longitudinal arch is the highest and most important of the three arches. It is composed of the calcaneus, talus, navicular, cuneiforms, and the first three metatarsals.

            The lateral longitudinal arch is lower and flatter than the medial arch. It is composed of the calcaneus, cuboid, and the fourth and fifth metatarsals.

            The transverse arch is composed of the cuneiforms, the cuboid, and the five metatarsal bases.

            The arches of the foot are maintained by the shapes of the bones as well as by ligaments and tendons.