Skeletal System study guide.docx

Anatomy & Physiology Dr. Lyons UW-Parkside [Skeletal Review With Questions] Basic Anatomical Review The Skeleton \*206 bones in the adult body\* Functions of the Skeleton Support Protection Locomotion Mineral Depository Blood Formation We only have one skeleton, but for teaching purpose...

Anatomy & Physiology Dr. Lyons UW-Parkside [Skeletal Review With Questions] Basic Anatomical Review The Skeleton \*206 bones in the adult body\* Functions of the Skeleton Support Protection Locomotion Mineral Depository Blood Formation We only have one skeleton, but for teaching purposes it is often broken down into the axial and appendicular skeletons: Axial Skeleton Cranium/skull Vertebral Column 7 cervical**\***; 12 thoracic; 5 lumbar; 5 sacral (fused); 4 coccygeal (fused) **\*** C1 is called Atlas C2 is called Axis C7 is sometimes called Cervical Prominens Ribs = Costae Sternum = manubrium; gladiolus or body; xiphoid process Appendicular Skeleton Shoulder blades = Scapulae Collar bones = Clavicles Upper Extremity humerus; radius; ulna; carpals (8 of 'em); metacarpals; phalanges+++ Pelvis ilium; ischium; pubis (also called innominate bone or os coxa when fused) Lower Extremity femur; patella; tibia; tarsals (7 of 'em); metatarsals; phalanges+++ +++ ONE is a phalanx, NOT a ~~Phalange~~ Types/Shapes of Bones Long Irregular Short Sesamoid Flat Bone, which is considered to be a type of connective tissue, is made of 1\. calcium carbonate (mineral salt) 2\. calcium phosphate (mineral salt) These minerals form "hydroxyapatite," which gives bones and teeth their rigidity 3\. collagen... protein with great tensile strength... forms the matrix 4\. water The mineral salts, hydroxyapatite, provide stiffness and compressive strength. Collagen is a protein that provides flexibility and tensile strength. Dehydrated bone will be significantly weakened and more susceptible to fracture. Bone is porous, and each bone manifests a different degree of porosity. Porous bone tends to have fewer mineral salts and, therefore, has decreased compressive strength. Based upon porosity, bone tissue can be separated into two different categories: Cortical & Trabecular bone. Cortical bone =\> mineral dense bone that is predominantly found in the diaphyses (shafts) of the long bones. Very necessary for weight bearing. Trabecular bone =\> less mineral dense bone, which is predominantly found in the epiphyses (ends) of long bones. Very necessary for absorbing shock. Bones can safely resist compression more than tension, and they can safely withstand tension more than shear forces. Bone is living tissue and is constantly being formed and resorbed, or remodeled. Osteoblasts form new bone cells, and osteoclasts resorb or tear down bone. In normal healthy adult persons, the activity of the osteoblasts approximately equals the activity of the osteoclasts. Mature bone cells are called osteocytes. Osteopenia =\> a condition marked by abnormally decreased bone mineral density and, consequent, bone weakness. Osteoporosis is even more severe than osteopenia and is marked by extremely severe decreased bone mineral density and, consequent, bone fragility or frailness. Osteoporosis =\> a disorder involving decreased bone mass and decreased strength with one or more resulting fractures. Osteoporosis is the most common metabolic disorder in the United States. Most common manifestation of Osteoporosis - deformation and fractures of lumbar vertebrae, the femoral neck at the hip, and the distal radius. *To combat osteoporosis, a balanced diet with sufficient calcium and magnesium is essential. Vitamin D, the "sunshine vitamin," is critical as well. Equally important is regular weight bearing exercises such as walking, jogging, and resistance training. Estrogen/testosterone therapy may be required as a last resort.* Osteoporotic fractures are more common in post-menopausal women and tend to manifest in the: - Neck of the femur - Bodies of the 4^th^ & 5^th^ Lumbar vertebrae - Radiocarpal joint of the wrist Wolff\'s Law =\> bone strength and mass increase and decrease as the functional forces on the bone increase and decrease. In other words, bone mass and density change according to the demands placed upon the bone. Weight bearing exercise is good for bone! Bone hypertrophy =\> increases in bone mass/mineral density due to a predominance of osteoblast activity. Bone atrophy =\> decreases in bone mass/mineral density due to a predominance of osteoclast activity. Joints or articulations serve which purposes? Growth, Movement, Shock Absorption Joints may be classified as: Synarthroses (no movement... necessary for growth and some shock absorption) Sutures of the skull; growth plates of long bones Amphiarthroses (little movement... important for shock absorption) pubic symphysis & intervertebral joints... the disks... the jelly donuts Diarthroses/Synovial Joints (free movement... also important for shock absorption) - 1. Actual cavity; 2. Encapsulated; 3. Synovial fluid; 4. Ends of bones covered with articular/hyaline cartilage Six subcategories: \- pivot.... atlantoaxial joint & radioulnar joints (both proximal & distal) \- ball and socket... glenohumeral & coxofemoral/acetabulofemoral joints \- hinge... humeroulnar & tibiofemoral & talocrural joints \- condyloid or ellipsoidal... radiocarpal & metacarpophalangeal joints (\#s 2-5) \- saddle... carpometacarpal joint of the thumb (only good example of a saddle joint in the body) \- gliding... intercarpals and intertarsals & facet/flipper joints in spine Joint Stability - The propensity of an articulation to resist displacement Stability α 1/Mobility... this means that as stability increases, mobility decreases, and vice versa. Note, Range of Motion (ROM) and flexibility are the same as "mobility." We, therefore, strive to acquire and maintain ***optimal stability (and mobility)***; NOT maximal stability (no mobility). What is "optimal stability?" This depends on the structure of the joints, the age and background of the person, and the demands that the person faces. Optimal stability (and mobility) is different for an 18-yr. old ballerina and a 44-yr. old librarian. Baseball players want less shoulder stability (more mobility) than powerlifters who want more stiffness (more stability and restricted mobility.) Factors that contribute to joint stability/mobility: \- joint ligaments and capsules \- muscle tension; agonist antagonist relationship \- fascia or connective tissue \- atmospheric pressure \- shape of the articulating surfaces of the bones (geometry, or architecture, of the articulation... ball & socket versus hinge, for example) Spinal Column Vertebrae: 7 cervical 12 thoracic - from the back... look like a giraffe C:\\Users\\Lyons\\AppData\\Local\\Microsoft\\Windows\\INetCache\\Content.MSO\\1E9D1321.tmp 5 lumbar (thickest bodies - bear the most weight) - from the back... look like a moose  5 sacral (fused in adults) 4 coccygeal (fused in adults)... some folks are born with more or less than 4 Spinous processes Transverse processes Body Vertebral Foramen Facets -- Superior & Inferior allow for articulations of adjacent vertebral arches... look like flippers Other Important Terms Lordosis (excessive lumbar lordosis is "swayback") Kyphosis (excessive thoracic kyphosis is "hunchback") Scoliosis Anatomical Position... Cardinal Planes & Cardinal Axes Anatomical Position and Directional Terms \| Anatomy and Physiology There is ONLY ONE ANATOMICAL POSITION... never write anatomical position**~~s~~** Cardinal Planes & Axes First, different books and different teachers will use different terms for the planes and axes. That is unfortunate because it can be confusing. I try to stick pretty close to the terminology that the NSCA uses. "Cardinal" means principal or primary planes or axes for analyzing movement. There are literally an infinite number of planes that we can move through about an infinite number of axes, but there are only three cardinal planes and their three associated axes. So, we have: The sagittal plane and the transverse (sideways) axis The frontal plane and the anteroposterior (front to back) axis The horizontal (or transverse) plane and longitudinal axis... I prefer to say "horizontal" plane  Planes Of Motion - Saggital Plane, Transverse Plane, Frontal Plane Note that technically, the above planes are mid-sagittal, mid-frontal, and mid-horizontal/transverse planes because they divide the body into halves. In the above picture, disregard the lines because they are confusing; the lines are actually depicting the cardinal axes. All planes that run parallel to the above shown planes are also considered sagittal, frontal, and/or horizontal planes. Thus, when flexing the left arm about the shoulder, the left upper extremity still moves in a sagittal plane about a transverse axis, it's just not the mid-sagittal plane. When you rotate your head left and right, it still occurs in a horizontal plane about a longitudinal axis, it's just not the mid-horizontal plane. Now the axes of rotation can be thought of as axles of a turning wheel. Remember, when we move about joints, we have rotary or circular motion. In order to turn the wheel, we must ask ourselves, which way would the axle (axis) have to be oriented? Imagine that you have a piece of paper, or actually take out a piece of paper if you like. Now, poke a pencil right through the center of the paper. Well, your paper represents the plane and the pencil is the axis. Now hold the paper in front of your face so that it is "paper-thin" and so that it is parallel to the walls on your left and right. This is a sagittal plane. Notice the position of your pencil. If we wish to turn the paper about the pencil while keeping it in the sagittal plane, then the pencil **must be** sideways (**transverse**). Now change the position of your paper so that you can read what's printed on it. Now the paper is parallel to the walls in front and back of you. And the pencil is now oriented front to back. If you wish to spin the paper about the pencil and keep it in the frontal plane, the pencil **must run** front to back (**anteroposterior**). And if you reorient the paper one last time so that it is flat and parallel with the floor and ceiling, then this is the horizontal plane. The pencil will run straight up and down or longitudinally. If you wish to spin the paper about the pencil and keep it in the horizontal plane, the pencil **must run** straight up and down (**longitudinal** like through a globe.) The cardinal axis must always be perpendicular to the plane to allow for circular movement in that plane. All movements in between cardinal planes occur in oblique or diagonal planes about oblique or diagonal axes.  If you look at this picture, you are already familiar with the Y and X axes of a graph. The Y axis represents the up and down or *longitudinal cardinal axis* for us. The X axis represents the sideways or *transverse axis* for us. The Z axis gives us a 3^rd^ dimension and runs front to back, and it represents the *anteroposterior axis* for us. Anatomical Directional Terms (I copied this off the internet and I altered it somewhat) **Anterior:** In front of, front\ **Posterior:** After, behind, following, toward the rear\ **Distal:** Away from, farther from the trunk or torso\ **Proximal:** Near, closer to the trunk or torso\ **Dorsal:** Essentially a zoology term that still pops up in human A&P occasionally; means posterior\ **Ventral:** Essentially a zoology term that still pops up in human A&P occasionally; means anterior\ **Superior:** Above, over... towards the head\ **Inferior:** Below, under... towards the feet\ **Lateral:** Toward the side, away from the mid-line\ **Medial:** Toward the mid-line, middle, away from the side Note "Middle" and "Medial" are different terms\ **Rostral:** Toward the front... literally towards the nose **Cephalo**... means towards the head\ **Caudal:** Toward the back, towards the tail It is said that humans develop motor control in a cephalocaudal manner... from head to tail... when we are very young\ **Bilateral:** Involving both sides of the body\ **Unilateral:** Involving one side of the body\ **Ipsilateral:** On the same side of the body\ **Contralateral:** On opposite sides of the body\ **Parietal:** Relating to a body cavity wall\ **Visceral:** Relating to organs within body cavities\ **Axial:** Around a central axis\ **Intermediate:** Between two structures... often called "middle" **Types of joint movements** **Flexion** -- bending a joint. This occurs when the angle of a joint decreases. For example, the elbow flexes when performing a biceps curl. The knee flexes in preparation for kicking a ball. **Extension** -- straightening a joint. This occurs when the angle of a joint increases, for example the elbow when throwing a shot put. The take-off knee extends when a high-jumper takes off (the other knee is flexed). **Hyperextension** -- is not a bad thing... it's just extension that continues beyond the anatomical position... so when you look down and tuck your chin, your cervical vertebrae/neck is flexed... if you then move to look straight ahead, you have extended your cervical vertebrae or caused neck extension.... If you continue and look up to see a bird in flight, then you have hyperextended your cervical vertebrae/neck. Note that hyperextended does not mean injured... sure, if you hyperextend too far, it will cause injury, but any movement taken too far will cause injury. **Abduction** -- movement away from the midline of the body in the frontal plane. This occurs at the hip and shoulder joints during a jumping jack movement. **Adduction** -- movement towards the midline of the body in the frontal plane. This occurs at the hip and shoulder, returning the arms and legs back to their original position from a jumping jack movement or when swimming breaststroke. **Adduction/Abduction also occur with the scapulae... squeezing the shoulder blades together is scapular adduction or Retraction and allowing them to separate fully is scapular abduction of Protraction** **Flexion and extension/hyperextension are opposites; abduction and adduction are opposites too.** **Horizontal Adduction... movement in the horizontal plane towards the midline of the body like when we squeeze the arms together during the pec deck exercise.** **Horizontal Abduction... movement in the horizontal plane away from the midline of the body like when we spread our arms during the pec deck exercise.** How To Do Pec Deck Flyes For Real Results - Form, Tips, and Mistakes **Lateral Flexion** **.... Occurs along the spine as one moves away from the midline in the frontal plane... trying to touch your shoulder with your ear is cervical lateral flexion... sliding your** **Hand down to touch the side of your knee is lumbar lateral flexion. Sometimes called spinal abduction.** **Reduction.... Occurs along the spine as one moves back towards the midline in the frontal plane... it is like lateral extension, but we call it reduction or spinal adduction rather than lateral extension.**  **Circumduction** -- this is NOT a PURE MOVEMENT, but combines flexion/extension/hyperextension and adduction/abduction to make circular movements. REVIEWING THE JOINT MOVEMENTS Name the motion in direction of arrow. - ppt video online download  **Rotation** -- this is where the limb or head turns around (pivots) its long axis, like using a screw driver. This occurs in the neck when one turns the head left and right to look for oncoming traffic or to signal "no." **To help remember the difference between rotation and circumduction, imagine there is a pen at the end of the body part. If the pen draws a dot, it\'s rotation. If the pen draws a circle, it\'s circumduction.** Joint Names You must know: **Atlantoaxial Joint**... actually an intervertebral joint between C~1~ & C~2~... allows for left/right rotation in horizontal plane about a longitudinal axis. **Intervertebral Joints**... general term for superior and inferior vertebrae separated by an intervertebral disk (jelly donut).... These are actually amphiarthroses Intervertebral joint: Bones, ligaments, movements \| Kenhub **Glenohumeral Joint**... shoulder proper... ball & socket... like a golf ball sitting on a quarter... allows for flexion/extension/hyperextension in a sagittal plane about a transverse axis; adduction/abduction in a frontal plane about an anteroposterior axis; internal/external rotation about a longitudinal axis; and horizontal adduction/horizontal abduction in a horizontal plane about a longitudinal axis. The shoulder can be circumducted as well. Note Adduction/Abduction are not the same as Horizontal Adduction/Horizontal Abduction **Scapulothoracic Mechanism**... not really a joint, but functions like one... this is the clavicle and shoulder blade and how the shoulder blade slides around on the back of the thorax. The clavicle and the scapula are collectively referred to as the shoulder girdle, which is different from the shoulder proper (glenohumeral joint). The scapula can elevate (shrug) & depress (force down); protract (move apart) & retract (squeeze together); and upwardly rotate & downwardly rotate. The scapula can "tilt" and "wing" as well. Scapulohumeral Rhythm... often the glenohumeral joint must function in concert with the scapulothoracic mechanism so that we may have normal upper extremity movements... the "dance" that is coordinated by the nervous system to get the muscles that move the humerus and the muscles that move the scapula to work together seamlessly is called scapulohumeral rhythm. Poor scapulohumeral rhythm can definitely cause poor performance and injuries. **Humeroulnar Joint**... the elbow proper... hinge... only allows for flexion/extension/hyperextension in sagittal plane about a transverse axis **Proximal & Distal Radioulnar Joints** (forearm)... pivot joints... allow for pronation and supination as radius turns about the fixed ulna in the horizontal plane about a longitudinal axis. **Intercarpal Joints**... joints between the carpals... gliding joints... collectively they allow for flexion/extension/hyperextension of the wrist in the sagittal plane about a transverse axis and ulnar/radial deviation in the frontal plane about an anteroposterior axis. There are 8 carpal bones in the wrist... "*PTs Love Sex, However, Can't Take Time*." This is a mnemonic for remembering the carpals... Pisiform, Triquetrum, Lunate and Scaphoid form the proximal row while Hamate, Capitate, Trapezoid, and Trapezium form the distal row.  **Carpometacarpal Joints** (digits \#2-\#5)... condyloid joints... allow for flexion/extension/hyperextension in sagittal plane about transverse axis & Abduction/Adduction of the fingers in the frontal plane about an anteroposterior axis. **Carpometacarpal Joint of the Thumb** (digit \#1) (in the anatomical snuff box)... this is actually a saddle joint that allows for abduction/adduction and flexion/extension of the thumb. Anatomical Snuffbox: Borders, contents and anatomy \| Kenhub  **Interphalangeal Joints...** Between the bones of the fingers and the toes too... these are hinge joints that allow for flexion/extension/hyperextension in sagittal plane about transverse axis. **Acetabulofemoral Joint or Coxofemoral Joint**.... These are names for the hip... ball & socket... allows for flexion/extension/hyperextension in a sagittal plane about a transverse axis; adduction/abduction in a frontal plane about an anteroposterior axis; internal/external rotation about a longitudinal axis; and horizontal adduction/horizontal abduction in a horizontal plane about a longitudinal axis. The hip can be circumducted as well. **Tibiofemoral Joint**... this is the knee... a hinge joint (actually a modified hinge)... allows for flexion/extension/hyperextension in sagittal plane about a transverse axis, but also allows for a tiny bit of rotation in the horizontal plane about a longitudinal axis, thus it is often called a "modified hinge." **Patellofemoral Joint**... this where the patella slides up and down the femur as extension and flexion of the knee take place. The patella acts like a bobsled moving up onto the distal anterior portion of the femur as the knee extends and it returns to the inferior part of the femur upon flexion of the knee. If the bobsled does not track properly, this will cause knee pain. Changes of patellar position in relation to the femoral component\... \| Download Scientific Diagram  **Talocrural Joint**... this is the ankle proper... it is a hinge joint that only allows for plantar flexion/dorsiflexion in the sagittal plane about a transverse axis. Note: plantar flexion is actually ankle flexion... dorsi flexion is actually ankle extension/hyperextension... because so many folks don't know anatomy, we just usually say plantar flexion and dorsi flexion. **Intertarsal Joints**... the joints between the tarsals... gliding joints... very important for shock absorption during locomotion... and the play a role in allowing for inversion and eversion of the foot (but not ankle) in the frontal plane about an anteroposterior axis. "*The Concerned Teacher Noticed Three Children Crying.*" This is a mnemonic for remembering the seven tarsal bones... Calcaneus, Talus, Navicular, 3 Cuneiform Bones... medial, middle, and lateral... Cuboid Conditions and Treatments \*\*\* Key Point: Pronation and supination are different movements in the upper and lower extremities. In the upper extremity, pronation and supination involve the radioulnar joints, thus, they are forearm movements. In the lower extremity, pronation and supination ARE COMBINED MOVEMENTS involving both the ankle (talocrural joint) and foot (intertarsal joints). Supination of the foot involves both plantar flexion of the talocrural joint AND inversion of the foot at the intertarsal joints. It also involves some forefoot adduction too. Pronation of the foot involves both dorsiflexion of the talocrural joint AND eversion of the foot at the intertarsal joints. It also involves some forefoot abduction as well.  pronation and supination \| Pronation, Inversions, Flat feet Some Review Questions... This is not an exhaustive list of questions... that is, you are responsible for everything covered in class/notes regarding the skeletal system. \#1. List five reasons that we need a skeleton... that is, five functions of the skeleton. \#2. T or F Bone, cartilage, tendons, aponeuroses, and ligaments are all types of connective tissue. All of these tissues contain collagen which is a protein with high tensile strength. \#3. What is hydroxyapatite? Would you expect this to be affected by osteopenia/osteoporosis? \#4. Bones are often categorized as 1. Long... 2. Short... 3. Flat... 4. Irregular... 5\. Sesamoid Identify three *long* bones Identify three *short* bones Identify three *flat* bones Identify three *irregular* bones What is the largest *sesamoid* bone in the body called? \#5. \_\_\_\_\_\_\_\_ tend to build bone and \_\_\_\_\_\_\_\_ tend to break bone down. a\. Osteoclasts; osteoblasts b\. Chondrocytes; osteoblasts c\. Osteoblasts; osteoclasts \#6. Bone is living tissue and as such it will specifically adapt to the imposed demands. That is, if bone is stressed, it will hypertrophy and thicken (become more mineral dense). If the stresses are removed from the bone, then the bone will atrophy (become less mineral dense) and osteoporosis will result. Thus, astronauts have big problems with bone atrophy due to the microgravity away from the earth, and in general we recommend that all people perform weight bearing exercises in order to prevent osteoporosis. The question is **"Whose law states that bone specifically adapts to the imposed demands?"** \#7. Remember that the endocrine and nervous systems effectuate change in a person. Parathormone and calcitonin are two very important hormones that affect the skeletal system. Which gland produces parathormone? Which gland produces calcitonin? Which hormone, parathormone or calcitonin, stimulates osteoclast activity? What effect would this have on bone density? Which hormone, parathormone or calcitonin, decreases osteoclast activity? What effect would this have on bone density? \#8. For convenience, we often divide the skeleton into the Axial and Appendicular Skeletons. Which bones are in the Axial Skeleton? Which bones are in the Appendicular Skelton? \#9. Which bones are at the top and back (superior/posterior) of your head? \#10. Which bone is at the back and bottom (posterior/inferior) of your head? \#11. Which bone is above your eyebrows? By the way, this is one of the hardest bones in the body. \#12. Which bone is associated with your auditory canal? \#13. This is a funky shaped skull bone... it kinda looks like a butterfly and it's at the base of the skull under the brain... what's its name? \#14. Which bone makes up the high part of the cheek just to the outside of the eye socket? \#15. Which bone makes up the upper jaw? \#16. Which bone makes up the lower jaw? \#17. Regarding the face, what are orbits? \#18. What is the foramen magnum? It's found in which bone? \#19. Which bone is often fractured when a person is strangled? They often mention this bone in crime shows like CSI. It's very important for speaking and swallowing. \#20. The vertebral column has 33 vertebrae (in most people). How many cervical vertebrae do we have? What is the name of C~1~? What is the name of C~2~? What is the name of C~7~? How many thoracic vertebrae do we have? What is the relationship of thoracic vertebrae and costae? When viewed from behind, thoracic vertebrae look like what kind of animal?  \#21. How many lumbar vertebrae do we have? When viewed from behind, lumbar vertebrae look like what kind of animal? \#22. T or F The sacral and coccygeal vertebrae are fused. \#23. Draw a vertebra and label the body, transverse processes and spinous process. Where is the vertebral foramen? Does C~1~ have a body? \#24. In between the cervical, thoracic, and lumbar vertebrae, we find jelly donuts... well they're like jelly donuts, anyway. What's the anatomical name for the jelly donuts? What is the outside of the jelly donut called? What's the jelly called? \#25. What is the anatomical name for each of the following? shoulder blade collar bone rib breast bone arm bone medial forearm bone lateral forearm bone thigh bone knee cap weight bearing bone in leg lateral bone in leg finger/toe proximal wrist bones (4 of 'em) distal wrist bones (4 of 'em) List the individual tarsal names bones in hand between wrist and fingers bones in foot between tarsals and toes \#26. Which three bones form the innominate bone, which is also called the os coxa? \#27. In this class, we use what is referred to as the "Functional Classification System" for the joints in the skeletal system. What is a synarthrosis? Identify one example of a synarthrosis. Are synarthroses least important for growth, movement, or shock absorption? What is an amphiarthrosis? Identify two examples of amphiarthroses. What is a diarthrosis? What are the six subcategories of diarthroses and provide at least one anatomical example of each? \#28. List the movements (ex. flexion, adduction, ulnar deviation, etc.) that each of the following can evince. cervical region glenohumeral joint shoulder girdle (scapula/clavicle) humeroulnar joint radioulnar joints wrist intercarpal joints interphalangeal joints vertebral column acetabulofemoral joint tibiofemoral joint talocrural joint intertarsal joints \#29. T or F Bone mass typically peaks at about age 45. \#30. T or F Menopause and "manopause" can greatly affect bone density. \#31. What is osteoarthritis? What is rheumatoid arthritis? \#32. Which two minerals are very important for strong bones and teeth? Which vitamin is critical for forming strong bones and teeth? Are these minerals and this vitamin typically found in dairy products? \#33. For the following, use terms such as flexes, hyperextends, internally rotates, abducts, etc. During a seated row, the glenohumeral joint \_\_\_\_\_\_\_\_\_\_ as we pull on the resistance. During a seated row, the humeroulnar joint \_\_\_\_\_\_\_\_\_\_ as we pull on the resistance. During a barbell back squat, the tibiofemoral joint \_\_\_\_\_\_\_\_ as we descend. During a barbell back squat, the talocrural joint \_\_\_\_\_\_\_\_ as we descend. During a barbell back squat, the acetabulofemoral joint \_\_\_\_\_\_\_\_ as we descend. When using a Pec Deck, the glenohumeral joint \_\_\_\_\_\_\_\_\_\_\_as the hands/forearms are brought together. When performing a dumbbell shrug exercise, the shoulder girdle \_\_\_\_\_\_\_\_\_\_\_\_ as the dumbbells are lowered.