NFL Injury Glossary

Welcome to the 4for4 Injury Glossary! You'll find a vast array of injuries that we cover on a weekly basis, with in-depth information as to how an injury occurs. You'll also find a severity chart of ligament sprains and muscle strains to refer to when reading my weekly injury columns. Ligament sprains/muscle strains follow the same grading, so hopefully it'll give you a better understanding of what the player is dealing with. It’s important to note that a sprain or strain is a tear in the tissue and that the severity plays a major role in determining recovery timetables.

Grade 1 – Overstretching of the tissue causes slight microtears in the tissue. Pain is usually present when pressing directly over affected area, but strength and range of motion are not overly compromised.

Grade 2 – Moderate microtear developments in the tissue due to a more significant overload of the tissue. Athlete may have some increased swelling, tenderness, and loss of range of motion/strength due to pain.

Grade 3 – Either a complete rupture of the tissue or a significant tear to the tissue. Bruising, swelling, pain are all significant. Athlete may or may not be able to move area due to pain and could require surgery depending on severity of tear and if there is any instability around the corresponding joint.


Foot/Ankle Injuries

Lateral Ankle Sprain - An inversion sprain is often referred to as "rolling" your ankle. The ligaments/tendons/muscles on the outside of the ankle get overstretched and cause pain/swelling, making it difficult to put full weight through the leg.

Eversion Ankle Sprain - An eversion ankle sprain is an ankle sprain where the foot is turned out and an external force causes the deltoid ligament (ligament that stabilizes the inner aspect of the ankle) to get overstretched. 

High Ankle Sprain - The ligaments/connective tissue that connect the tibia and fibula (the bones of the lower leg), and just above the ankle, is what is affected in a high ankle sprain. Injury to this tissue is usually caused when the foot/ankle is rotated and the bones of the lower leg are fixed.

Achilles Tendon Rupture - The Achilles tendon is the main tendon that connects your calf muscle to your heel bone. Its primary function is to help distribute force to the bone from the muscle and also to help with pushing off the foot. 

Tibia Fracture - The tibia is the main shin bone in the lower leg. Direct trauma or a sudden twist or change of direction can cause stress to the bone that it cannot withstand, which can lead to a fracture.

Fibula Fracture - The tibia and fibula are the bones that make up lower leg. The fibula is the bone on the lateral aspect of the lower leg that is an attachment point for many muscles, tendons, and ligaments. A fracture to the fibula usually occurs when the ankle or lower leg is put into an extreme range of motion that the bone can’t handle.

Bruised Fibula - The fibula is one of two bones in the lower leg. The fibula is the bone on the outer aspect of the lower leg, and direct trauma to the fibula can cause swelling, pain, and potential nerve irritation due to the location of the peroneal nerve around the fibular head at the top of the bone.

Lisfranc Sprain - The foot is broken up into three regions: the rearfoot, midfoot, and forefoot. A lisfranc injury is a disruption of the stability in the bones/ligaments between the midfoot and forefoot. There can be a fracture, a tear in the ligaments, or both, which causes immediate swelling and pain. Walking becomes very difficult as the midfoot/forefoot region is the primary area of strain when you push off your foot.

Sprained Foot - There are 33 joints in the foot, with many muscles, ligaments, and tendons attaching to each joint. The main role of the foot is to help dissipate forces as the foot lands and pushes off the ground. A sprain can occur when overloading the joint by putting excessive pressure by running, twisting, or pushing off of that area.

Turf Toe - Repetitive, extreme ranges of motion when trying to sprint/run, can cause irritation to the ligaments around the big toe, which can cause pain. The athlete will be unable to push off the toe when running without discomfort which makes it difficult to try and play through.

Strained Calf - Your calf muscle's main responsibility is to help lift your heel off the ground and propel your body forward when attempting to run or walk. Forceful, repetitive contractions of the calf can lead to overstretching of the calf, which can cause pain.

Dislocated Ankle - A dislocated ankle usually involves the bones of the ankle and the bones of the lower leg (tibia, fibula) shifting out of place, causing complete disruption of the ligaments that help stabilize the area.

Jones Fracture - Fracture to the proximal aspect of the 5th metatarsal is considered a Jones fracture. This area of the metatarsal gets poor blood supply so often times surgerons will opt to place a screw into the fracture to help stabilize it and also to allow improved healing. 

Plantar Fascitis -The plantar fascia is a thick, dense band of connective tissue on the bottom side of the foot. It's responsible for helping maintain the arch in your foot and to distribute forces especially when trying to push off the foot. Repetitive strain to the plantar fascia causes inflammation to the tissue, with prolonged irritation possibly leading to a tear. A tear to the plantar fascia can be very painful, as any pressure in the area of pain can cause discomfort.


Knee Injuries

ACL Tear - The anterior cruciate ligament (ACL) is one of the main ligaments in the knee that helps prevent excessive twisting and torque on the knee. ACL tears usually occur when trying to change direction when the leg is planted, or by trauma through direct contact to the knee.

Sprained MCL - The medial collateral ligament (MCL) is the main ligament on the inside part of the knee that helps with stabilizing the knee. Ligament sprains occur to this region when a direct force is applied from the outside of the knee, which causes the knee to buckle in towards the other knee. An MCL sprain can also occur when trying to change direction or when attempting to cut.

Sprained LCL - The lateral collateral ligament is the main supporting ligament on the outside of the knee. A direct blow to the inside of the knee causes the LCL to stretch beyond its capacity and can lead to a tear. A tear can also happen when attempting to cut or twist as the leg is planted.

Sprained PCL - The posterior cruciate ligament (PCL) is the other main ligament in the knee, along with the ACL, that helps stabilize the knee. The PCL prevents the lower leg from moving backwards on the femur and resists rotational or twisting motions. PCL injuries usually occur with direct trauma to the lower leg that causes the leg to hyperextend, or from falling on the knee when it is fully bent.

Meniscus Tear – The meniscus is a small c-shaped cartilage that sits inside the knee joint. The meniscus helps shock absorb force when putting pressure through the leg and helps resist against twisting and turning motions. Fast, sharp motions can cause different types of tears in the meniscus. Depending on the location and size of the tear, it can lead to buckling, catching, and instability in the knee which could require surgery depending on function.

Hamstring Strain - The hamstring muscle is the primary muscle in the back of the thigh responsible for bending the knee and extending the hip. When it relates to sports, it's a very important muscle in aiding to accelerate/decelerate the lower body to allow proper running and cutting.

Quadriceps Strain - The quadriceps is the main muscle in the front of the thigh. It helps straighten the leg and stabilize the leg (in addition to other muscles) when fully putting weight through the leg. Most quadriceps strains occur either in the middle of the muscle belly or towards the insertion point down by the knee.

Patellar Tendon Tear - The patellar tendon is the main tendon that comes from the quadriceps muscle on the front of your thigh that attaches to the tibia (your shin bone). The main function of the patellar tendon is to distribute forces from the quadriceps muscle to allow the leg to stay straight and to also help control bending when standing. Rupture of this tendon causes complete failure of the quadriceps muscle to straighten the leg and also put any weight as it is being applied to the leg.

Dislocated Patella – The patella is the small bone in the front of the knee that helps with mechanical advantage of your quadriceps to function properly. Quick lateral movements or force contractions of the quadriceps can cause the kneecap to dislocate, with dislocations usually occurring to the outside part of the leg.

Bruised Knee - A direct blow to the knee or in the surrounding area can lead to trauma to the soft tissue structures and possibly to the bone as well. Bone bruises can be very painful and hard to manage as they can cause immediate swelling which will limit mobility. The pain can also cause a reduction in strength which can make rehab more difficult to progress quickly through.  


Hip Injuries

Hip Pointer - Direct trauma to the front side of the hip bone can cause swelling, pain and an inability to flex the hip without discomfort.

Strained hip - Direct trauma to or repetitive use of the muscles/tendons/ligaments around the hip can cause pain.

Labral tear – The labrum is a thick band of cartilage in the hip joint to help deepen the joint and further provide support for the hip. Rotational movements or movements that force the hip into its limits can cause a tear in the labrum. The athlete will report catching in the hip, deep ache in the hip and groin pain.

Strained Groin - The adductors are the muscles on the inside of your thigh known as your groin muscles. Sprinting, cutting, and twisting motions can cause the muscle/tendon junction to fail causing pain in that region. Higher grade strains of the adductor muscles can lead to partial tearing of the muscle off the bone, either where the muscle originates or inserts.

Sports Hernia - Your pelvic bone has attachments from the lower part of your abdominal muscles (in this case, mainly your obliques) and your groin muscles. Overloading of that area from repetitive twisting and turning motions can cause irritation of that tissue, which can cause the soft tissue structures to tear. Surgery is usually required for this type of injury to repair the abdominal tissue.


Shoulder Injuries

Broken Collarbone - Your clavicle (also known as your collarbone) is the main bone that connects your shoulder girdle to your sternum. The main job of your collarbone is to help with shoulder and upper arm movement as well as being a main site for many muscular attachments. Direct trauma to the clavicle from a fall or by being driven to the ground can cause excessive force that the bone can’t handle, which can lead to a fracture.

Rotator Cuff Tear - The rotator cuff is a group of 4 muscles that help stabilize the head of the humerus (ball) in the socket (glenoid). If the rotator cuff is injured, it can prevent an athlete from being able to lift their arm overhead or in other directions without pain.

Labrum Tear – The labrum is a thick band of cartilage in the shoulder joint to help deepen the joint and further provide significant support for the shoulder. Rotational movements, fast movements into a range of motion the shoulder isn’t prepared for, and landing on the shoulder with the arm outstretched are some potential ways you can tear the labrum. The athlete will report catching in the shoulder, deep ache in the shoulder, and pain in the surrounding area where the tear occurred.

AC Joint Sprain Shoulder (Separated Shoulder) – Direct trauma to the acromioclavicular (AC) joint can cause immediate inflammation in the joint and possible disruption of the ligaments that help support it. Normally an AC joint sprain is caused when falling directly on the shoulder.

Shoulder Dislocation - The shoulder is made up of a ball and socket joint, with the majority of its stability coming from muscles, tendons, and ligaments. A dislocation is when the ball comes out of the socket and stays out, which can cause tears and ruptures to many of the soft tissue structures around the shoulder joint.

Shoulder Sprain - Due to the amount of mobility in the shoulder, there are many muscles, tendons, and ligaments that help support it. Direct trauma, or moving the shoulder into an extreme range of motion unexpectedly can cause irritation to those structures which can cause pain.

Torn Pectoral Muscle – The pectoral muscles originate from your sternum and collarbone, with it inserting into the humerus/shoulder. When the pectoral muscle is torn, it can lead to pain when trying to reach the arm back, and any throwing motion can lead to pain/instability due to its insertion onto the humerus.

Elbow/Hand Injuries

Bruised Hand/Fractured Hand - Direct trauma to the hand can cause immediate swelling and pain. If the force of the trauma exceeds the capacity the bone is able to withstand, then a fracture may occur. Depending on where the bruising/swelling is located, it can make gripping activities very painful.

Elbow Dislocation - The elbow is made up of your humerus (long bone of upper arm) and the two bones in your forearm, the radius and ulna. A dislocation occurs when either the humerus or the ulna/radius come out of normal alignment and stay out of alignment due to a traumatic force.

Sprained Elbow - repettive throwing motion can lead to irritation to the forearm muscles on the inner aspect of the elbow and potentially the ulnar collateral ligament, which is normally compromised in those that require Tommy John Surgery. 

Finger Dislocation – Grabbing jerseys, hitting the hand on the helmet, or many other ways can cause a finger to dislocate. The finger comes out of socket and stays out of place, which causes disruption to the surrounding soft tissue in the area. Most finger dislocations are reduced (put back in place), splinted, with players able to return to the field depending on the severity.

Spine Conditions

Strained Neck - Spinal pain can be experienced when going into extreme ranges of motion, particularly when being tackled. There are many structures in the neck that can generate pain, and being forced into a certain position can cause irritation and inflammation which can cause further discomfort.

Lumbar Strain - Spinal pain can be experienced when going into extreme ranges of motion, particularly when being tackled. There are many structures in the low back that can generate pain, and being forced into a certain position can cause irritation and inflammation which can cause further discomfort.

Disc Herniation - The discs between your vertebrae act as shock absorbers to help distribute forces and reduce strain on the spine. The disc is made up of an outer fibrous layer, and a soft, gelatinous middle to allow the disc to deform based on spinal movement. Repetitive, quick movements can cause the outer fibrous layer to degenerate which can cause the inner gelatinous layer to “herniate” out. Depending on the severity of the herniation, some can have just localized pain, while others can have pain that can radiate down their leg due to the disc compressing the nerve root that exits the spinal column. (radiculopathy).

Broken RibA broken rib is usually caused from direct trauma to the area. A fracture that is more significant can lead to a collapsed lung (pneumothorax), where the rib punctures the lung and causes it to collapse, making it difficult to breathe.

Rib ContusionDirect trauma to the ribcage area can cause pain, irritation, and bruising to the muscles and cartilage that help support the area. The bruising and inflammation sustained from the injury can irritate the cartilage in between each rib, making it difficult to breathe.

Stinger - Stingers usually involve a combined motion of the neck and shoulder being forced in opposite directions, which overstretches the nerves that run through that region, known as the brachial plexus. The athlete feels immediate pain, which can then radiate down into the hands/fingers depending on the severity. Some athletes feel pain, but can cause other symptoms such as numbness, tingling, burning, etc.

Concussion - Concussions are an insult to the brain from direct trauma. The brain suffers microtrauma with a multitude of symptoms which can occur depending on where the trauma is located.

For a complete, in-depth look at the NFL concussion and return to play protocol, follow the link below:

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